Electrolytic processing apparatus and method

ABSTRACT

This invention relates to an electrolytic processing apparatus and method useful for processing a conductive material formed in the surface of a substrate, or for removing impurities adhering to the surface of a substrate. An electrolytic processing apparatus, including, a processing electrode that can come close to a workpiece, a feeding electrode for feeding electricity to the workpiece, an ion exchanger disposed in the space between the workpiece and the processing and the feeding electrodes, a fluid supply section for supplying a fluid between the workpiece and the ion exchanger, and a power source, wherein the processing electrode and/or the feeding electrode is electrically divided into a plurality of parts, and the power source applies a voltage to each of the divided electrode parts and can control voltage and/or electric current independently for each of the divided electrode parts.

TECHNICAL FIELD

This invention relates to an electrolytic processing apparatus andmethod, and more particularly to an electrolytic processing apparatusand method useful for processing a conductive material formed in thesurface of a substrate, especially a semiconductor wafer, or forremoving impurities adhering to the surface of a substrate.

The present invention also relates to a fixing method and structure foran ion exchanger for use in electrolytic processing for processing aconductive material in the surface of a substrate, such as asemiconductor wafer, or removing impurities adhering to the surface ofthe substrate, and further relates to an electrolytic processingapparatus which is provided with the ion exchanger-fixing structure.

BACKGROUND ART

In recent years, instead of using aluminum or aluminum alloys as amaterial for forming interconnection circuits on a substrate such as asemiconductor wafer, there is an eminent movement towards using copper(Cu) which has a low electric resistivity and high electromigrationresistance. Copper interconnects are generally formed by filling copperinto fine recesses formed in the surface of a substrate. There are knownvarious techniques for forming such copper interconnects, including CVD,sputtering, and plating. According to any such technique, a copper filmis formed in the substantially entire surface of a substrate, followedby removal of unnecessary copper by chemical mechanical polishing (CMP)

FIGS. 1A through 1C illustrate, in sequence of process steps, an exampleof forming such a substrate W having copper interconnects. As shown inFIG. 1A, an insulating film 2, such as an oxide film of SiO₂ or a filmof low-k material, is deposited on a conductive layer 1 a in whichsemiconductor devices are formed, which is formed on a semiconductorbase 1. Contact holes 3 and trenches 4 for interconnects are formed inthe insulating film 2 by the lithography/etching technique. Thereafter,a barrier layer 5 of TaN or the like is formed on the entire surface,and a seed layer 7 as an electric supply layer for electroplating isformed on the barrier layer 5.

Then, as shown in FIG. 1B, copper plating is performed onto the surfaceof the substrate W to fill the contact holes 3 and the trenches 4 withcopper and, at the same time, deposit a copper film 6 on the insulatingfilm 2. Thereafter, the copper film 6 and the barrier layer 5 on theinsulating film 2 are removed by chemical mechanical polishing (CMP) soas to make the surface of the copper film 6 filled in the contact holes3 and the trenches 4 for interconnects and the surface of the insulatingfilm 2 lie substantially on the same plane. An interconnection composedof the copper film 6 as shown in FIG. 1C is thus formed.

Components in various types of equipments have recently become finer andhave required higher accuracy. As sub-micro manufacturing technology hascommonly been used, the properties of materials are largely influencedby the processing method. Under these circumstances, in such aconventional machining method that a desired portion in a workpiece isphysically destroyed and removed from the surface thereof by a tool, alarge number of defects may be produced to deteriorate the properties ofthe workpiece. Therefore, it becomes important to perform processingwithout deteriorating the properties of the materials.

Some processing methods, such as chemical polishing, electrolyticprocessing, and electrolytic polishing, have been developed in order tosolve this problem. In contrast with the conventional physicalprocessing, these methods perform removal processing or the like throughchemical dissolution reaction. Therefore, these methods do not sufferfrom defects, such as formation of an altered layer and dislocation, dueto plastic deformation, so that processing can be performed withoutdeteriorating the properties of the materials.

An electrolytic processing method that utilizes an ion exchanger hasbeen developed. According to this method, an ion exchanger mounted on aprocessing electrode and an ion exchanger mounted on a feeding electrodeare allowed to be close to or into contact with the surface of aworkpiece. A voltage is applied from a power source to between theprocessing electrode and the feeding electrode while a liquid, such asultrapure water, is supplied from a fluid supply section to between theprocessing and feeding electrodes and the workpiece, thereby carryingout removal processing of the surface layer of the workpiece.

FIG. 2 schematically shows a conventional electrolytic processingapparatus generally employed for such electrolytic processing. Theelectrolytic processing apparatus includes a processing electrode 52 andan ion exchanger 54 that is mounted on the processing electrode 52.Depending upon the material of a workpiece W, the processing electrode52 is connected to the cathode or the anode of a power source 56, andthe workpiece W is connected to the opposite pole, and the workpiece Wis utilized as a feeding electrode. FIG. 2 shows the case where theprocessing electrode 52 is connected to the cathode of the power source56 and the workpiece W is connected to the anode of the power source 56.The processing electrode 52 concentrates e.g. OH⁻ ions, in anelectrolytic solution capable of dissolving the atoms of theto-be-processed surface WA of the workpiece W, at the to-be-processedsurface WA closed to the processing electrode 52 to cause a reactionbetween the atoms of the workpiece W and OH⁻ ions, thereby processingthe workpiece W. In the case of a semiconductor substrate W, a film of aconductive material formed in the substrate surface WA is removed by theprocessing electrode 52 in order to form semiconductor interconnects orcontacts.

According to the conventional electrolytic processing apparatus, an ionexchanger for use in such electrolytic processing is tight on theexposed surface of a processing electrode or a feeding electrode, and isfixed on the electrode or at a peripheral portion of e.g. a support thatsupports the electrode, usually by screwing or using an adhesive tape orthe like at a peripheral portion of the ion exchanger.

In recent years, as interconnects of the circuit to be formed in asemiconductor substrate has become finer with higher integrated densityof the semiconductor device, it is desired to improve the flatness ofthe processed surface of the semiconductor substrate. Therefore, thereis a demand for a technique that can improve the uniformity of theprocessing rate over the entire to-be processed surface.

Metals of the platinum group or their oxides have become candidates foran electrode material for use in forming a capacitor, which utilizes ahigh dielectric material, on a semiconductor substrate. Among themruthenium, because of its good film-forming properties and goodprocessibility for patterning, is being progressively studied as afeasible material.

A ruthenium film can be formed on a substrate generally by sputtering orCVD. In either method, deposition of the ruthenium film on the entirefront surface of a substrate, including the peripheral region, iscarried out. As a result, a ruthenium film is formed also in theperipheral region of the substrate and, in addition, the back surface ofthe substrate is unavoidably contaminated with ruthenium.

The ruthenium film formed on or adhering to the peripheral region orback surface of a substrate, i.e. the non-circuit region of thesubstrate, is not only unnecessary, but can also causecross-contamination during later transfer, storage and variousprocessing steps of the substrate whereby, for instance, the performanceof a dielectric material can be lowered. Accordingly, during the processfor forming a ruthenium film or after carrying out some treatments ofthe formed ruthenium film, it is necessary to completely remove theunnecessary ruthenium film. Further, in the case of using ruthenium asan electrode material for forming a capacitor, a step for removing partof a ruthenium film formed on the circuit region of a substrate isneeded.

According to the conventional electrolytic processing apparatus as shownin FIG. 2, however, because of unevenness of the electric current valuedue to the shape of the processing electrode 52 or to the influence ofthe reaction products or gas bubbles generated during processing, theprocessing rate is likely to be uneven in the to-be-processed surfaceWA.

On the other hand, chemical mechanical polishing (CMP), for example,generally necessitates a complicated operation and control, and needs aconsiderably long processing time. In addition, a sufficient cleaning ofa substrate must be conducted after the polishing treatment. This alsoimposes a considerable load on the slurry or cleaning liquid wastedisposal. Accordingly, there is a strong demand for omitting CMPentirely or reducing a load upon CMP. Also in this connection, it is tobe pointed out that though a low-k material, which has a low dielectricconstant, is expected to be predominantly used in the future as amaterial for the insulating film of a semiconductor substrate, the low-kmaterial has a low mechanical strength and therefore is hard to endurethe stress applied during CMP processing. Thus, also from thisstandpoint, there is a demand for a technique that enables theflattering of a substrate without giving any stress thereto.

Further, a method has been reported which performs CMP processingsimultaneously with plating, viz. chemical mechanical electrolyticpolishing. According to this method, the mechanical processing iscarried out to the growing surface of a plating film, causing theproblem of denaturing of the resulting film.

Further, though it is desired that an ion exchange for use inelectrolytic processing be tightly fixed on the exposed surface of aprocessing electrode or a feeding electrode, as described above, inorder to ensure evenness of the processing accuracy, it has practicallybeen difficult to keep the ion exchanger fixed tightly on the electrode.

Thus, when continuing electrolytic processing while an ion exchanger isfixed on an electrode by screwing or with an adhesive tape, the fixingof ion exchanger is likely to become incomplete, so that the ionexchanger can move easily, impairing evenness of the processingaccuracy.

DISCLOSURE OF INVENTION

The present invention has been made in view of the above situation inthe background art. It is therefore a first object of the presentinvention to provide an electrolytic processing apparatus and methodthat can control a processing rate distribution over the entireto-be-processed surface of a workpiece, thereby improving uniformity ofthe processing rate or improving evenness of the processed surface.

It is a second object of the present invention to provide anelectrolytic processing apparatus and method which, while omitting a CMPtreatment entirely or reducing a load upon a CMP treatment to the leastpossible extent, can process a conductive material formed in the surfaceof a substrate to flatten the material, or can remove (clean) extraneousmatter adhering to the surface of a workpiece such as a substrate.

It is a third object of the present invention to provide a fixing methodand structure for an ion exchanger that can easily and quickly fix anion exchanger tightly on the surface of an electrode, and to provide anelectrolytic processing apparatus provided with the ion exchanger-fixingstructure.

In order to achieve the above object, the present invention provides anelectrolytic processing apparatus, comprising: a processing electrodethat can come close to or into contact with a workpiece; a feedingelectrode for feeding electricity to the workpiece; an ion exchangerdisposed in at least either between the workpiece and the processingelectrode, or between the workpiece and the feeding electrode; a fluidsupply section for supplying a fluid between the workpiece and the ionexchanger; and a plurality of power sources, each for applying a voltagebetween the processing electrode and the feeding electrode; wherein atleast one of the processing electrode and the feeding electrode iselectrically divided into a plurality of parts, and the power sourcesapply each voltage to each of the divided electrode parts and cancontrol at least one of voltage and electric current independently foreach of the divided electrode parts.

With the provision of the processing electrode and the feedingelectrode, the electrical division of at least one of the processingelectrode and the feeding into a plurality of parts, and the independentcontrol of at least one of the voltage and the electric current for eachof the divided electrode parts, the electrolytic processing apparatuscan improve uniformity of the electric field intensity over the entiresurface of the to-be-processed surface of a workpiece, thereby improvinguniformity of the processing rate, or can control a processing ratedistribution to improve evenness of the processed surface.

To “control at least one of voltage and electric current independentlyfor each of the divided electrode parts” herein includes the cases of(1) controlling at least one of the voltage and the electric currentbetween each of divided processing electrode parts and an undividedfeeding electrode, (2) controlling at least one of the voltage and theelectric current between an undivided processing electrode and each ofdivided feeding electrode parts, and (3) controlling at least one of thevoltage and the electric current between each of divided processingelectrode parts (N parts) and each of divided feeding electrode parts (Nparts) in a plurality of circuits (N circuits) formed by the processingelectrode parts and the feeding electrode parts.

The fluid may be ultrapure water, pure water, a liquid having anelectric conductivity of not more than 500 μS/cm. The use as the fluidof ultrapure water, pure water, a liquid having an electric conductivityof not more than 500 uS/cm or an electrolytic solution makes it possibleto carry out a clean processing without leaving impurities on thesurface of a workpiece, thereby simplifying a cleaning step afterelectrolytic processing. The electric conductivity value herein refersto the corresponding value at 1 atm, 25° C.

It is preferred that respectively different constant voltages be appliedat least one time to each of the divided electrode parts. Thisfacilitates control of the end point of processing.

It is possible to apply respectively different constant voltages atleast one time to at least two of the divided electrode parts. Thisenables a more flexible control. The term “constant voltage” hereinrefers to a substantially constant voltage that can be regarded as beingpractically constant.

It is also preferred that an electric current or a voltage, whichchanges with time, be supplied to each of the divided electrode parts.This facilitates control of the end point of processing.

It is possible to supply an electric current or a voltage, which changeswith time, to at least two of the divided electrode parts. This enablesa more flexible control.

The present invention provides an electrolytic processing method,comprising: providing a processing electrode and a feeding electrode, atleast one of which is electrically divided into a plurality of parts;allowing a workpiece to be close to or in contact with the processingelectrode; feeding electricity from the feeding electrode to theworkpiece; disposing an ion exchanger between at least either betweenthe workpiece and the processing electrode, or between the workpiece andthe feeding electrode; supplying a fluid between the workpiece and theion exchanger; applying a voltage to each of the divided electrodeparts; and controlling at least one of voltage and electric currentindependently for each of the divided electrode parts.

The present invention also provides an electrolytic processingapparatus, comprising: a processing electrode; a feeding electrode forfeeding electricity to the workpiece; a holder for holding the workpiecethat can come close to or into contact with the processing electrode; anion exchanger disposed in at least either between the workpiece and theprocessing electrode, or between the workpiece and the feedingelectrode; a power source for applying a voltage between the processingelectrode and the feeding electrode; a fluid supply section forsupplying a fluid between the workpiece and at least one of theprocessing electrode and the feeding electrode, in which the ionexchanger is disposed; and a drive section for allowing the workpieceheld by the holder and the processing electrode to make a relativemovement; wherein a dummy member, at least the surface of which has anelectric conductivity, is disposed outside of the periphery of theworkpiece. It is preferred that the dummy member make the area of theportion of the workpiece facing the processing electrode constant duringthe relative movement of the workpiece and the processing electrode.

FIGS. 3 and 4 illustrate the principle of the electrolytic processingthat utilizes an ion exchanger. FIG. 3 shows the ionic state when an ionexchanger 62 a mounted on a processing electrode 64 and an ion exchanger62 b mounted on a feeding electrode 66 are brought into contact with orclose to a surface of a workpiece 60, while a voltage is applied via apower source 67 between the processing electrode 64 and the feedingelectrode 66, and a liquid 68, e.g. ultrapure water, is supplied from aliquid supply section 69 between the processing electrode 64, thefeeding electrode 66 and the workpiece 60. FIG. 4 shows the ionic statewhen the ion exchanger 62 a mounted on the processing electrode 64 isbrought into contact with or close to the surface of the workpiece 60and the feeding electrode 66 is directly contacted with the workpiece60, while a voltage is applied via the power source 67 between theprocessing electrode 64 and the feeding electrode 66, and the liquid 68,such as ultrapure water, is supplied from the liquid supply section 69between the processing electrode 64 and the workpiece 60.

When a liquid like ultrapure water that in itself has a largeresistivity is used, it is preferred to bring the ion exchanger 62 ainto contact with the surface of the workpiece 60. This can lower theelectric resistance, lower the requisite voltage and reduce the powerconsumption. The “contact” in the present electrolytic processing doesnot imply “press” for giving a physical energy (stress) to a workpieceas in CMP.

Water molecules 70 in the liquid 68 such as ultrapure water aredissociated efficiently by using the ion exchangers 62 a, 62 b intohydroxide ions 73 and hydrogen ions 74. The hydroxide ions 73 thusproduced, for example, are carried, by the electric field between theworkpiece 60 and the processing electrode 64 and by the flow of theliquid 68, to the surface of the workpiece 60 opposite to the processingelectrode 64 whereby the density of the hydroxide ions 73 in thevicinity of the workpiece 60 is enhanced, and the hydroxide ions 73 arereacted with the atoms 60 a of the workpiece 60. The reaction product 76produced by this reaction is dissolved in the liquid 68, and removedfrom the workpiece 60 by the flow of the liquid 68 along the surface ofthe workpiece 60. Removal processing of the surface of the workpiece 60is thus effected.

As will be appreciated from the above, the removal processing accordingto this processing method is effected purely by the electrochemicalinteraction between the reactant ions and the workpiece. Thiselectrolytic processing thus clearly differs in the processing principlefrom CMP according to which processing is effected by the combination ofthe physical interaction between an abrasive and a workpiece, and thechemical interaction between a chemical species in a polishing liquidand the workpiece. According to the above-described method, the portionof the workpiece 60 facing the processing electrode 64 is processed.Therefore, by moving the processing electrode 64, the workpiece 60 canbe processed into a desired surface configuration.

As described above, the removal processing of the electrolyticprocessing is effected solely by the dissolution reaction due to theelectrochemical interaction, and is clearly distinct in the processingprinciple from CMP in which processing is effected by the combination ofthe physical interaction between an abrasive and a workpiece, and thechemical interaction between a chemical species in a polishing liquidand the workpiece. Accordingly, the electrolytic processing can conductremoval processing of the surface of a workpiece without impairing theproperties of the material of the workpiece. Even when the material of aworkpiece is of a low mechanical strength, such as the above-describedLow-k material, removal processing of the surface of the workpiece canbe effected without any physical damage to the workpiece. Further,compared to the conventional electrolytic processing which useelectrolytic solution as a processing liquid, by using a liquid havingan electric conductivity of not more than 500 μS/cm, preferably purewater, more preferably ultrapure water, as a processing liquid, it ispossible to reduce remarkably contamination of the surface of aworkpiece, and dispose easily of waste liquid after the processing.

According to the present invention, as described above, the workpiece 60and the processing electrode 64 are moved relatively so as to move theportion of the workpiece 60 facing the processing electrode 64, so thatprocessing of the entire surface of the workpiece 60 can be carried out.Depending upon the shapes of the workpiece 60 and the processingelectrode 64, however, the area of the portion of the workpiece 60facing the processing electrode 64, i.e. the face-to-face area, maychange with the relative movement of the workpiece 60 and the processingelectrode 64. For example, in the case of FIG. 5A, as the processingelectrode 64 moves relative to the workpiece 60, the area of the portionof the workpiece 60 facing the processing electrode 64 changes from S₁to S₂. The processing rate is proportional to the current density(=current value/face-to-face area). When processing is carried out at aconstant current value, the processing rate is fast in a smallface-to-face area and is slow in a large face-to-face area.Consequently, the processing rate cannot be made equal over the entiresurface of the workpiece 60, failing to effect a uniform processing ofthe workpiece 60. In such a case, it may be considered to properlycontrol the current value according to the face-to-face area so as toequalize the processing rate over the entire surface of the workpiece60. It is, however, difficult to properly control the current valueaccording to the face-to-face area that varies during processing.

According to the present invention, the provision of a dummy memberoutside of the periphery of a workpiece can make the face-to-face areaconstant, thereby realizing a uniform processing. More specifically, asshown in FIG. 5B, by the provision of a dummy member 78 outside of theworkpiece 60, the area of the processing electrode 64 facing theworkpiece 60 and the dummy member 78, i.e. the face-to-face area, isalways constant (S₃) irrespective of the relative movement of theworkpiece 60 and the processing electrode 64. Accordingly, the currentdensity can be made always constant even with a constant current value,making it possible to equalize the processing rate over the entiresurface of the workpiece 60 and carry out a uniform processing stably.

In electrochemical processing, reactant ions are moved to the surface ofthe workpiece 60 by the electric field between the processing electrode64 and the workpiece 60 (feeding electrode 66), and the surface of theworkpiece 60 is processed by the ions. Accordingly, in order to carryout a uniform processing of the workpiece 60, it is necessary to makethe intensity of the electric field between the processing electrode 64and the workpiece 60 uniform over the entire surface of the workpiece60. However, uniformity of the electric field intensity can be impairedby the shapes of the electrode and the workpiece 60. For example, in thecase of FIG. 6A, processing progresses between the processing electrode64 (cathode) and the workpiece 60 (anode), and the electric flux lines(arrows) and the isoelectric lines (solid lines) are dense at the endportion of the workpiece 60 compared to the other portion, that is, theelectric field concentration occurs at the end portion of the workpiece60. Accordingly, the amount of reactant ions increases at the endportion of the workpiece 60 whereby the processing rate at the endportion becomes significantly higher than the other portion. As aresult, as shown in FIG. 6B, the processing amount is large locally atthe end portion A of the workpiece 60. Thus, the workpiece 60 cannot beprocessed uniformly.

According to the present invention, as shown in FIG. 6C, since the dummymember 78 is provided outside of the periphery of the workpiece 60, theabove-described electric field intensity concentration occurs in thedummy member 78. This makes it possible to make the electric fieldintensity at the end portion of the workpiece 60 the same as the otherportion, thereby equalizing the processing rate over the entire surfaceof the workpiece 60. The present invention thus makes it possible toequalize the processing rate over the entire surface of the workpiece 60and carry out a uniform processing stably.

It is preferred that the conductive portion of the dummy member beformed of an electrochemically inactive material. By forming at leastthe surface of the dummy member of an electrochemically inactivematerial, the dummy member can be prevented from being processed,together with the workpiece, during electrolytic processing.

It is preferred that the conductive portion of the dummy member beformed of the same material as the workpiece. By forming at least thesurface of the dummy member of the same material as the workpiece, thereaction at the dummy member can be made the same as the reaction at theworkpiece, whereby uniformity of the processing can be further improved.

It is preferred that a buffering member be disposed between theworkpiece and the dummy member. The buffering member can absorb a shockto the workpiece. The buffering member is preferably formed of amaterial having a lower hardness than the dummy member.

The present invention also provides an electrolytic processingapparatus, comprising: a processing electrode having a larger diameterthan a workpiece; a feeding electrode for feeding electricity to theworkpiece; a holder for holding the workpiece that can come close to orinto contact with the processing electrode; an ion exchanger disposed inat least either between the workpiece and the processing electrode, orbetween the workpiece and the feeding electrode; a power source forapplying a voltage between the processing electrode and the feedingelectrode; a fluid supply section for supplying a fluid to the spacebetween the workpiece and at least one of the processing electrode andthe feeding electrode, in which the ion exchanger is disposed; and adrive section for allowing the workpiece held by the holder and theprocessing electrode to make a relative movement in such a state thatthe center of movement of the processing electrode lies within the rangeof the workpiece.

In electrolytic processing, the processing amount is determined by thefrequency of presence of a processing electrode over a workpiece and theapplied voltage. Accordingly, when it is intended to process the wholesurface of a workpiece into a uniform flat surface, it is necessary tomake the presence frequency of a processing electrode equal over theentire surface of the workpiece. For example, when the workpiece has adisk shape, like a semiconductor substrate, and the processing electrodealso has a disk shape and its diameter is smaller than the diameter ofthe workpiece, the workpiece and the processing electrode may be allowedto make a relative movement so that the processing electrode can bepresent over the entire surface of the workpiece, thereby processing theentire surface of the workpiece. Even with such a method, however, thepresence frequency of processing electrode can vary at some points ofthe workpiece, leading to unevenness of the processing amount. Evennessof the presence frequency of processing electrode may be increased whenthe diameter of the processing electrode is larger than the diameter ofa workpiece. However, the processing electrode, which is a metal, shouldnecessarily be larger, and thus the weight increase becomes a problem.Further, depending upon the state of contact between an ion exchangerand a workpiece, the processing amount is likely to vary at the contactend.

According to the electrolytic processing apparatus of the presentinvention, since the processing electrode has a larger diameter than aworkpiece, a high processing rate can be obtained. In addition, sincethe center of movement of the processing electrode lies within the rangeof the workpiece during electrolytic processing, the presence frequencyof the processing electrode over the surface of the workpiece can bebest equalized. Furthermore, it becomes possible to use a considerablysmaller processing electrode, leading to a remarkable downsizing andweight saving of the whole apparatus. The center of movement of theprocessing electrode is the center of scroll movement when theprocessing electrode makes a scroll movement, and is the center ofrotation when the processing electrode makes a rotational movement.

The present invention also provides an electrolytic processingapparatus, comprising: a processing electrode having a larger diameterthan a workpiece; a feeding electrode for feeding electricity to theworkpiece; a holder for holding the workpiece that can come close to orinto contact with the processing electrode and the feeding electrode; apower source for applying a voltage between the processing electrode andthe feeding electrode; a fluid supply section for supplying a fluidbetween the workpiece and the processing and feeding electrodes; and adrive section for allowing the workpiece held by the holder and theprocessing and feeding electrodes to make a relative movement in such astate that the center of movement of the processing electrode lieswithin the range of the workpiece.

The present invention also provides an electrolytic processingapparatus, comprising: a processing electrode having a larger diameterthan a workpiece; a plurality of feeding electrodes disposed in aperipheral portion of the processing electrode; a holder for holding theworkpiece that can come close to or into contact with the processingelectrode; an ion exchanger disposed in at least either between theworkpiece and the processing electrode or between the workpiece and thefeeding electrodes; a power source for applying a voltage between theprocessing electrode and the feeding electrodes; a fluid supply sectionfor supplying a fluid to the space between the workpiece and at leastone of the processing electrode and the feeding electrodes, in which theion exchanger is disposed; and a drive section for allowing theworkpiece held by the holder and the processing electrode to make arelative movement in such a state that at least one of the feedingelectrodes always feeds electricity to the workpiece.

Since a workpiece cannot be processed with the region where a feedingelectrode is present, the processing rate is low with the region inwhich the feeding electrode is present, compared to the other region. Itis therefore preferable to make the area (region) occupied by a feedingelectrode smaller in order to reduce the influence of the feedingelectrode upon the processing rate. From this viewpoint, according tothe electrolytic processing apparatus of the present invention, aplurality of feeding electrodes having a small area are disposed in aperipheral portion of the processing electrode, and at least one of thefeeding electrodes is allowed to come close to or into contact with aworkpiece during the relative movement. This makes it possible to reducean unprocessible region as compared to the case of disposing aring-shaped feeding electrode in the peripheral portion of theprocessing electrode, thereby preventing a peripheral portion of theworkpiece from remaining unprocessed.

The processing electrode preferably comprises an outer processingelectrode defined by the peripheral portion in which the feedingelectrodes are disposed, and an inner processing electrode positioned onthe inner side of the outer processing electrode. Further, it ispreferred that the power source control independently the respectivevoltages or electric currents applied to the outer processing electrodeand to the inner processing electrode. By thus dividing the processingelectrode into the two parts respectively positioned in the region wherethe feeding electrodes have an influence on the processing rate and inthe region where the feeding electrodes have no influence on theprocessing rate, and controlling the respective processing rates at thetwo processing electrode parts independently, a lowering of theprocessing rate in the region where the feeding electrodes are presentcan be prevented. Thus, by making the processing rate at the outerprocessing electrode relatively higher than the processing rate at theinner processing electrode, it becomes possible to suppress theinfluence by the presence of the feeding electrodes and realize auniform processing rate over the entire surface of the processingelectrode.

The present invention also provides an electrolytic processingapparatus, comprising: a processing electrode having a larger diameterthan a workpiece; a plurality of feeding electrodes disposed in aperipheral portion of the processing electrode; a holder for holding theworkpiece that can come close to or into contact with the processingelectrode and the feeding electrodes; a power source for applying avoltage between the processing electrode and the feeding electrodes; afluid supply section for supplying a fluid between the workpiece and theprocessing and feeding electrodes; and a drive section for allowing theworkpiece held by the holder and the processing and feeding electrodesto make a relative movement in such a state that at least one of thefeeding electrodes always feeds electricity to the workpiece.

The present invention also provides an electrolytic processing method,comprising: providing a processing electrode having a larger diameterthan a workpiece and a feeding electrode for feeding electricity to theworkpiece; disposing an ion exchanger between the workpiece and at leastone of the processing electrode and the feeding electrode; applying avoltage between the processing electrode and the feeding electrode;allowing the workpiece to be close to or into contact with theprocessing electrode; supplying a fluid between the workpiece and atleast one of the processing electrode and the feeding electrode, inwhich the ion exchanger is disposed; and allowing the workpiece and theprocessing electrode to make a relative movement in such a state thatthe center of movement of the processing electrode always lies withinthe range of the workpiece, thereby processing the surface of theworkpiece.

The present invention also provides an electrolytic processing method,comprising: providing a processing electrode having a larger diameterthan a workpiece and a feeding electrode for feeding electricity to theworkpiece; applying a voltage between the processing electrode and thefeeding electrode; allowing the workpiece to be close to or into contactwith the processing electrode and the feeding electrode; supplying afluid between the workpiece and the processing electrode and feedingelectrode; and allowing the workpiece and the processing and feedingelectrodes to make a relative movement in such a state that the centerof movement of the processing electrode always lies within the range ofthe workpiece, thereby processing the surface of the workpiece.

The present invention also provides an electrolytic processing method,comprising: providing a processing electrode having a larger diameterthan a workpiece and a plurality of feeding electrodes disposed in aperipheral portion of the processing electrode; disposing an ionexchanger between the workpiece and at least one of the processingelectrode and the feeding electrodes; applying a voltage between theprocessing electrode and the feeding electrodes; allowing the workpieceto be close to or into contact with the processing electrode; supplyinga fluid between the workpiece and at least one of the processingelectrode and the feeding electrodes, in which the ion exchanger isdisposed; and allowing the workpiece and the processing electrode tomake a relative movement in such a state that at least one of thefeeding electrodes always feeds electricity to the workpiece, therebyprocessing the surface of the workpiece.

The present invention also provides an electrolytic processing method,comprising: providing a processing electrode having a larger diameterthan a workpiece and a plurality of feeding electrodes disposed in aperipheral portion of the processing electrode; applying a voltagebetween the processing electrode and the feeding electrodes; allowingthe workpiece to be close to or into contact with the processingelectrode and the feeding electrodes; supplying a fluid between theworkpiece and the processing and feeding electrodes; and allowing theworkpiece and the processing and feeding electrodes to make a relativemovement in such a state that at least one of the feeding electrodesalways feeds electricity to the workpiece, thereby processing thesurface of the workpiece.

The present invention also provides an electrolytic processing method,comprising: allowing a workpiece to be close to or into contact with aplurality of processing electrodes; applying a voltage between theprocessing electrodes and a feeding electrode for feeding electricity tothe workpiece; supplying a fluid between the workpiece and at least oneof the processing electrodes and the feeding electrode; and allowing theprocessing electrodes and the workpiece to make a relative movement sothat a plurality of processing electrodes, which are uneven in theprocessing amount per unit time, pass every point in the to-be-processedsurface of the workpiece, thereby processing the surface of theworkpiece.

Electrochemical processing is effected through an electrochemicalinteraction between reactant ions and a workpiece, and the processingrates at various points in the surface of the workpiece basicallydepend, except the physical properties of the workpiece, on the currentdensity and the frequency of presence of a processing electrode over theworkpiece. In practice, reaction products produced at the surface of theworkpiece by the electrochemical reaction between the workpiece and thereactant ions during processing, and gas bubbles generated by a sidereaction at the surfaces of the workpiece and the electrode impedemovement of the reactant ions to the surface of the workpiece. Further,because of the electrochemical interaction, the reaction rate changeswith a change in temperature, etc. Due to these factors, the processingrate can vary within the same processing electrode when a singleprocessing electrode is employed. Even when a plurality of processingelectrodes are employed, the processing rate can vary between theprocessing electrodes.

Accordingly, when it is intended to process the surface of a workpieceat a uniform processing rate with the use of a plurality of processingelectrodes, in view of the above facts, removal of the reaction productsand gas bubbles and equalization of the presence frequency of processingelectrodes may be carried out. However, variation of the processing ratebetween the respective processing electrodes can nevertheless occur,making equalization of the processing rate on an nm/min order difficult.According to the electrolytic processing method of the presentinvention, the processing electrodes and a workpiece are allowed to makea relative movement so that a plurality of processing electrode passevery point in the to-be-processed surface of the workpiece, therebyeliminating variation of the processing rate between the processingelectrodes and equating the processing rate. This enables an nm/minorder of equalization of the processing rate over the entire surface ofthe workpiece.

Preferably, the plurality of processing electrodes are disposed suchthat the presence frequencies of processing electrodes at every pointsin the to-be-processed surface of the workpiece become substantiallyequal during the relative movement. The plurality of processingelectrodes are preferably of the same shape.

It is preferred that the feeding electrode comprise a plurality ofelectrodes. The plurality of feeding electrodes are preferably disposedsuch that the presence frequencies of feeding electrodes at every pointsin the to-be-processed surface of the workpiece become substantial equalduring the relative movement.

The relative movement is preferably one of a rotational movement, areciprocating movement, an eccentric rotational movement and a scrollmovement, or a combination thereof.

It is preferred that an ion exchanger be disposed between the workpieceand at least one of the processing electrodes and the feedingelectrodes.

The fluid is preferably ultrapure water, pure water, a liquid having anelectric conductivity of not more than 500 μS/cm, or an electrolyticsolution.

The present invention also provides an electrolytic processing method,comprising: allowing a workpiece to be close to or into contact with aprocessing electrode; applying a voltage between the processingelectrode and a feeding electrode for feeding electricity to theworkpiece; supplying a fluid between the workpiece and at least one ofthe processing electrode and the feeding electrode; and allowing theprocessing electrode and the workpiece to make a relative movement sothat a plurality of points in the processing electrode, which are unevenin the processing amount per unit time, pass every point in theto-be-processed surface of the workpiece, thereby processing the surfaceof the workpiece.

The present invention also provides an electrolytic processingapparatus, comprising: a plurality of processing electrodes; a feedingelectrode for feeding electricity to the workpiece; a holder for holdingthe workpiece that can come close to or into contact with the processingelectrodes; a power source for applying a voltage between the processingelectrodes and the feeding electrode; a fluid supply section forsupplying a fluid between the workpiece and one of the processingelectrodes and the feeding electrode; and a drive section for allowingthe processing electrodes and the workpiece to make a relative movementso that a plurality of processing electrodes, which are uneven in theprocessing amount per unit time, pass every point in the to-be-processedsurface of the workpiece held by the holder.

The present invention also provides an electrolytic processing apparatuscomprising: a processing electrode; a feeding electrode for feedingelectricity to a workpiece; a holder for holding the workpiece that cancome close to or into contact with the processing electrodes; a powersource for applying a voltage between the processing electrode and thefeeding electrode; a fluid supply section for supplying a fluid betweenthe workpiece and at least one of the processing electrode and thefeeding electrode; and a drive section for allowing the processingelectrode and the workpiece to make a relative movement so that aplurality of points in the processing electrode, which are uneven in theprocessing amount per unit time, pass every point in the to-be-processedsurface of the workpiece held by the holder.

The present invention provides a fixing method for fixing an ion changerfor use in electrolytic processing on an electrode, comprising:positioning an ion exchanger between an electrode support, whichsupports an electrode with its surface exposed, and a fixing jigengageable with the periphery of the electrode support; and engaging thefixing jig with the electrode support, thereby fixing the ion exchangerwith its peripheral portion sandwiched in between the fixing jig and theelectrode support.

According to the fixing method, an ion exchanger is evenly stretchedoutwardly due to frictional force between the fixing jig, the ionexchanger and the electrode support produced when simply pressing thefixing jig into engagement with the electrode support, and the ionexchanger is thus evenly stretched into a tense state, whereby the ionexchanger can be automatically fixed tightly on the exposed surface ofthe electrode.

Preferably, the fixing jig consists of a pair of divided jigs, and thepair of divided jigs, with the ion exchanger at its peripheral portionsandwiched in therebetween, is pressed into engagement with theelectrode support.

By thus provisionally fixing the ion exchanger in the divided fixingjigs by sandwiching the ion exchanger at its peripheral portion inbetween the divided jigs before pressing the divided jigs intoengagement with the electrode support, slipping between the ionexchanger and the fixing jig upon the press-in is prevented, whereby theion exchanger can be fixed always in a tense state.

The present invention also provides a method for fixing an ion exchangerfor use in electrolytic processing on an electrode, comprising:disposing an ion exchanger-fixing jig outside of an electrode; holdingthe ion exchanger by the ion exchanger-fixing jig; and attaching the ionexchanger-fixing jig to the electrode while allowing the ion exchangerto be supported in a tense state on the electrode.

The present invention provides a fixing structure for fixing an ionexchanger for use in electrolytic processing on an electrode,comprising: an electrode support that supports an electrode with itssurface exposed; and a fixing jig engageable with the periphery of theelectrode support; wherein the electrode support and the fixing jig fixan ion exchanger by sandwiching therebetween a peripheral portion of theion exchanger and stretching the ion exchanger over the surface of theelectrode.

It is preferred that the fixing jig consist of a pair of divided jigs,and an outer peripheral portion of the ion exchanger, outside of theportion covering the electrode support, is sandwiched in between thefixing jigs.

The present invention also provides an electrolytic processing apparatuscomprising an ion exchanger-fixing device, the ion exchanger-fixingdevice including; an electrode support that supports an electrode withits surface exposed; and a fixing jig engageable with the periphery ofthe electrode support; wherein the ion exchanger-fixing device fixes anion exchanger by sandwiching a peripheral portion of the ion exchangerin between the electrode support and the fixing jig.

It is preferred that the electrode support and the fixing jig be allowedto move relatively to fix the ion exchanger by sandwiching theperipheral portion of the ion exchanger in between the electrode supportand the fixing jig.

This enables an exchange of an ion exchanger for a new one. Thus, whenan ion exchanger is stained, for example, at least one of the fixing jigand the electrode support is moved in a direction away from each otherto release the fixing of the ion exchanger and, after allowing the ionexchanger to travel a necessary distance, the at least one of the fixingjig and the electrode support is moved in a direction closer to eachother to fix the ion exchanger, thereby carrying out exchanges of ionexchangers in a successive manner.

It is preferred that the ion exchanger, disposed between the electrodesupport and the fixing jig, be capable of traveling.

In a preferred embodiment, the ion exchanger has an endless form and iscapable of traveling in one direction, and a regeneration section forregenerating the ion exchanger is provided in a traveling route of theion exchanger.

This makes it possible to fix part of the endless ion exchanger and usethat part for processing while regenerating other part of the ionexchanger, not in use for processing, in the regeneration section, andafter allowing the ion exchanger to travel in one direction, fix theregenerated part of ion exchanger for use in processing. A repetition ofthis operation enables circulation and repeated uses of the endless ionexchanger.

In another preferred embodiment, the ion exchanger is capable oftraveling in two directions, and two regeneration sections forregenerating the ion exchanger are provided on both sides of theelectrode support in the traveling direction of the ion exchanger.

This makes it possible to fix part of the ion exchanger and use thatpart for processing while regenerating other part of the ion exchanger,not in use for processing, in one of the regeneration sections, andexchange the part of the ion exchanger that has been used in processingfor the regenerated part of ion exchanger. A repetition of thisoperation enables repeated uses of the long ion exchanger.

The above and other objects, features, and advantages of the presentinvention will be apparent from the following description when taken inconjunction with the accompanying drawings which illustrates preferredembodiments of the present invention by way of example.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A through 1C are diagrams illustrating, in sequence of processsteps, an example of the formation of copper interconnects;

FIG. 2 is a cross-sectional view schematically showing a conventionalelectrolytic processing apparatus;

FIG. 3 is a diagram illustrating the principle of electrolyticprocessing according to the present invention as carried out by allowinga processing electrode and a feeding electrode, both having an ionexchanger mounted thereon, to be close to or into contact with asubstrate (workpiece), and supplying a liquid between the processing andfeeding electrodes and the substrate (workpiece);

FIG. 4 is a diagram illustrating the principle of electrolyticprocessing according to the present invention as carried by mounting anion exchanger only on the processing electrode and supplying a liquidbetween the processing electrode and the substrate (workpiece);

FIG. 5A is a diagram illustrating “face-to-face” area in the case of notproviding a dummy member, and FIG. 5B is a diagram illustrating“face-to-face” area in the case of providing a dummy member;

FIG. 6A is a diagram illustrating the electric field intensity in thecase of not providing a dummy member, FIG. 6B is a diagram illustratinga workpiece after processing in the case of FIG. 6A, and FIG. 6C is adiagram illustrating the electric field intensity in the case ofproviding a dummy member;

FIG. 7 is a cross-sectional view schematically showing an electrolyticprocessing apparatus according to a first embodiment of the presentinvention;

FIG. 8 is a diagram showing the connection between the processingelectrode and the wiring, and the connection between the substrate andthe wiring in the electrolytic processing apparatus of FIG. 7;

FIG. 9 is a plan view of the electrolytic processing apparatus of FIG.7;

FIG. 10 is a cross-sectional view schematically showing an electrolyticprocessing apparatus according to a second embodiment of the presentinvention;

FIG. 11 is a plan view of the electrode holder of the electrolyticprocessing apparatus of FIG. 10;

FIG. 12 is a diagram showing the connection between the processingelectrode and the wiring, and the connection between the substrate andthe wiring in the electrolytic processing apparatus of FIG. 10;

FIG. 13 is a plan view showing the processing electrode and the feedingelectrode of an electrolytic processing apparatus according to a thirdembodiment of the present invention;

FIG. 14 is a diagram showing the connection between the processingelectrode and the wiring, and the connection between the substrate andthe wiring in the electrolytic processing apparatus of FIG. 13;

FIG. 15 is a plan view illustrating a case of division of an ionexchanger;

FIG. 16 is a plan view of a substrate processing apparatus provided withan electrolytic processing apparatus according to the present invention;

FIG. 17 is a cross-sectional view schematically showing an electrolyticprocessing apparatus according to a fourth embodiment of the presentinvention;

FIG. 18A is a plan view showing the rotation-preventing mechanism of theelectrolytic processing apparatus of FIG. 17, and FIG. 18B is asectional view taken along the line A-A of FIG. 18A;

FIG. 19 is a cross-sectional view schematically showing the substrateholder and the electrode section of the electrolytic processingapparatus of FIG. 17;

FIG. 20 is a plan view showing the relationship between the substrateholder and the electrode section of FIG. 17;

FIG. 21A is a graph showing the relationship between the electriccurrent and time in electrolytic processing of the surface of asubstrate, the substrate having in the surface a laminated film composedof two different materials, and FIG. 21B is a graph showing therelationship between the voltage and time in electrolytic processing ofthe surface of a substrate, the substrate having in the surface alaminated film composed of two different materials;

FIG. 22 is a perspective view schematically showing an electrolyticprocessing apparatus according to a fifth embodiment of the presentinvention;

FIG. 23 is a plan view of the electrolytic processing apparatus of FIG.22;

FIG. 24 is a cross-sectional view schematically showing an electrolyticprocessing apparatus according to a sixth embodiment of the presentinvention;

FIG. 25 is a cross-sectional view schematically showing the substrateholder and the electrode section of the electrolytic processingapparatus of FIG. 24;

FIG. 26 is a plan view showing the relationship between the electrodesection and the substrate of FIG. 25;

FIG. 27 is a cross-sectional view schematically showing a substrateholder and an electrode according to another embodiment of the presentinvention;

FIG. 28 is a plan view of an electrode section according to stillanother embodiment of the present invention;

FIG. 29 is a perspective view of an electrode section according to stillanother embodiment of the present invention;

FIG. 30 is a plan view showing an electrode section according to stillanother embodiment of the present invention together with a substrate;

FIG. 31 is a cross-sectional view schematically showing an electrolyticprocessing apparatus according to a seventh embodiment of the presentinvention;

FIG. 32 is a plan view of the electrolytic processing apparatus of FIG.31;

FIG. 33 is a plan view showing the electrode section of the electrolyticprocessing apparatus of FIG. 31;

FIG. 34 is an enlarged view of a portion of the electrode section ofFIG. 33;

FIG. 35 is a plan view showing an electrode section according to aneighth embodiment of the present invention;

FIG. 36 is an enlarged view of a portion of the electrode section ofFIG. 35;

FIG. 37 is a plan view showing an electrode section according to a ninthembodiment of the present invention;

FIG. 38 is an enlarged view of a portion of the electrode section ofFIG. 37;

FIG. 39 is a cross-sectional view schematically showing an electrolyticprocessing apparatus according to a tenth embodiment of the presentinvention, which is provided with a fixing structure for ion exchanger;

FIG. 40 is a cross-sectional view showing the state of the fixingstructure before fixing an ion exchanger to the electrode support;

FIG. 41 is a cross-sectional view showing the main portion of a fixingstructure for ion exchanger according to another embodiment;

FIGS. 42A and 42B are cross-sectional views showing the main portion ofa fixing structure for ion exchanger according to still anotherembodiment;

FIG. 43 is a cross-sectional view schematically showing an electrolyticprocessing apparatus according to eleventh embodiment of the presentinvention;

FIG. 44 is a cross-sectional view of the main portion of the ionexchanger-fixing device provided in the electrolytic processingapparatus of FIG. 43, showing the state of the device before fixing ofan ion exchanger;

FIG. 45 is a cross-sectional view showing the main portion of anelectrolytic processing apparatus according to a twelfth embodiment ofthe present invention;

FIG. 46 is a cross-sectional view showing the main portion of anelectrolytic processing apparatus according to a thirteenth embodimentof the present invention;

FIG. 47 is a cross-sectional view showing an example of a regenerationsection;

FIG. 48 is a cross-sectional view showing another example of aregeneration section; and

FIG. 49 is a plan view schematically showing a variation of the ionexchanger-fixing device.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will now be describedwith reference to the drawings. Though the below-described embodimentsrefer to application to electrolytic processing apparatuses which use asubstrate as a workpiece to be processed and remove (polish) copper orthe like formed on the surface of the substrate, the present inventionis of course applicable to other workpiece.

FIG. 7 is a partly sectional block diagram schematically showing anelectrolytic processing apparatus 50 according to a first embodiment ofthe present invention. The electrolytic processing apparatus 50comprises an electrode holder 12 for holding a processing electrode 18as an electrode, an electrode-rotating shaft 13 mounted to the electrodeholder 12, a substrate holder 14, provided above the electrode holder12, for attracting and holding a substrate W as a workpiece or as afeeding electrode, and a substrate-rotating shaft 15 mounted to thesubstrate holder 14. According to this embodiment, the substrate Wfunctions as a feeding electrode. The electrolytic processing apparatus50 further includes a power source 23 for applying a voltage or anelectric current between the processing electrode 18 and the substrateW, as will be described hereinbelow.

The electrolytic processing apparatus 50 is also provided with a hollowmotor 41 as a substrate-rotating means for rotating the substrate holder14 via the substrate-rotating shaft 15 (rotation about the central axisof the substrate-rotating shaft 15), a hollow motor 42 as anelectrode-rotating means for rotating the electrode holder 12 via theelectrode-rotating shaft 13 (rotation about the central axis of theelectrode-rotating shaft 13), a pivot arm 43, a pivot shaft 44 and apivoting motor 45 as substrate-pivoting means for pivoting the substrateholder 14 to a position right above the electrode holder 12 or pivotingthe substrate holder 14 horizontally from the position right above theelectrode holder 12, a ball screw 46 and a vertical movement motor 47 asvertical movement means for raising the substrate holder 14 away fromthe electrode holder 12 or lowering it near to the electrode holder 12,and a not-shown electrolytic solution supply means as a fluid supplymeans for supplying an electrolytic solution 49 as a fluid or as aliquid. The pivot arm 43 is driven by the pivoting motor 45, and pivotsthe substrate holder 14 about the pivot shaft 44. The ball screw 46 isdriven by the vertical movement motor 47, and raises and lowers thepivot shaft 44, the pivot arm 43 and the substrate holder 14.

The electrode holder 12 has a generally discoid shape, and is disposedhorizontally. A circumferential wall 16 is formed at the periphery ofthe upper surface 12B of the electrode holder 12. A depression 17 as afluid supply section is formed inside the circumferential wall 16. Thedisk-shaped processing electrode 18 is mounted horizontally on the uppersurface 16B of the circumferential wall 16. A through-hole 19 as a fluidsupply section is formed in the center of the electrode holder 12. Theprocessing electrode 18 is divided into seven parts by insulators 40.FIG. 7 does not show the actual sectional view of the processingelectrode 18, but illustrates a pattern of the seven divisions. In theentirely of the divided parts (hereinafter referred to as processingelectrode parts 18-1 through 18-7), there are formed a number ofthrough-holes 29 as a fluid supply section for supplying theelectrolytic solution 49 to the substrate W (only one through-hole 29for each of the processing electrode parts 18-1 through 18-7 is depictedin FIG. 7 for illustration purpose).

An ion exchanger 35 is mounted on the upper surface of the processingelectrode 18. The ion exchanger 35 is divided into seven parts inaccordance with the processing electrode parts 18-1 through 18-7, andthe respective parts are spaced from one another with interstices 35C.The ion exchanger 35 is divided into the same plan shapes as theprocessing electrode parts 18-1 through 18-7. It is possible tointerpose insulators between the divided ion exchangers 35 by insertingthe insulators in the interstices 35C, as in the case of the processingelectrode 18. In this case, the insulators should not protrude from theprocessing surface of the ion exchanger 35. FIG. 7 does not show theactual sectional view of the ion exchanger 35, but illustrates a patternof the seven divisions.

A circular film-like ion exchanger 35 (non-divided form) may be mountedon the upper surface 18B of the processing electrode 18 such that itcovers the entire upper surface 18B. The outermost radius of the ionexchanger 35 and the processing electrode 18 is designed to be almostthe same as the radius of the substrate W respectively.

The ion exchanger 35 may have at least one of cation-exchange groups andanion-exchange groups. In a preferred embodiment, the ion exchange 35have both of cation-exchange group and anion-exchange group that may bealternately disposed concentrically or radially in a plane, oralternately disposed in layers in the thickness direction.

The electrode-rotating shaft 13 of a hollow columnar shape is mountedvertically to the lower surface 12A of the electrode holder 12. A hollowpassage 20 as a fluid supply section is formed in the electrode-rotatingshaft 13. The hollow passage 20 communicates with the through-hole 19 ofthe electrode holder 12. The hollow motor 42 is connected to the lowerend 13A of the electrode-rotating shaft 13. A hollow portion 42C of thehollow motor 42, as a fluid supply section, communicates with the hollowpassage 20. A wire 24, connected to the lower surface 18A of theprocessing electrode 18, passes through the depression 17, thethrough-hole 19, the hollow passage 20 and the hollow portion 42C, andthrough a slip ring 26 provided at the lower end 42A of the hollow motor42, and is connected to the power source 23. An electrolytic solutionsupply inlet 28 as a fluid supply section is formed in the slip ring 26,and the electrolytic solution supply inlet 28 communicates with thehollow portion 42C. The not-shown electrolytic solution supply meanssupplies the electrolytic solution 49 to the electrolytic solutionsupply inlet 28 of the slip ring 26.

The substrate holder 14 has a disk shape, and is disposed horizontally.The substrate holder 14 attracts and holds the substrate W as aworkpiece in an attraction portion 14C. A through-hole 21 is formed inthe center of the substrate holder 14. The substrate holder 14 has, inthe portion to be contacted with the substrate W, a number of not-shownsuction holes that are connected to a not-shown vacuum source.

The substrate-rotating shaft 15 has a hollow columnar shape, and ismounted vertically to the upper surface 14B of the substrate holder 14.A hollow passage 22 is formed in the substrate-rotating shaft 15, andthe hollow passage 22 communicates with the through-hole 21 of thesubstrate holder 14. The hollow motor 41 is connected to the upper end15B of the substrate-rotating shaft 15. A hollow portion 41C of thehollow motor 41 communicates with the hollow passage 22. The hollowmotor 41 is connected to the lower surface 43A of the pivot arm 43 inthe vicinity of its free end 43C. A hollow portion 48 (shown with thebroken lines) is formed in the pivot arm 43 extending from theconnection with the hollow motor 41, and the hollow portion 48communicates with the hollow portion 41C.

A wire 25, connected to the upper surface WB of the substrate W, passesthrough the through-hole 21, the hollow passage 22, the hollow portion41C and the hollow portion 48, and through a slip ring 27 mounted to theupper surface 43B of the pivot arm 43 in the vicinity of its free end43C, and further through the pivot arm 43 and a hollow portion 39 (shownwith the broken lines) formed in the pivot shaft 44, and is connected tothe power source 23. The electrolytic processing apparatus 50 of thisembodiment is of the direct feeding type that feeds electricity directlyto the substrate W. The substrate W is disposed in parallel with theprocessing electrode 18.

The details of the wires 24, 25 will now be described with reference toFIG. 8 in the case where the processing electrode 18 is divided intoseven parts. In FIG. 8, the portion of the substrate holder 14 incontact with the substrate W is partly cut off in order to illustratethe state of wiring of the wire 25 to the substrate W. In FIG. 7, thewires 24, 25 are respectively drawn as a single wire and a single powersource 23 is drawn such that they form a single circuit. In fact,however, each of the processing electrode parts 18-1 through 18-7 isconnected to one wire 24, and is further connected at the point rightabove the processing electrode parts 18-1 through 18-7 to one wire 25.Further, the respective wires 24, 25 are connected to separate powersources 23 to form separate circuits. The respective circuits are sodesigned that at least one of the voltage and the electric currentbetween each of the processing electrode parts 18-1 through 18-7 and afeeding electrode can be controlled independently by means of anot-shown controller. The respective circuits may be so designed thatrespectively different constant voltages and constant electric currentsare applied alternately at least one time and are controlledindependently by means of the not-shown controller. In FIG. 8, adepiction of the through-hole 29 is omitted. The term “constant voltage”or “constant electric current” herein includes substantially constantvoltage or electric current that can be regarded as practicallyconstant.

The operation of the electrolytic processing apparatus 50 of thisembodiment will now be described with reference to FIG. 7.

The substrate W is placed on the attraction portion 14C of the substrateholder 14, and attracted and held thereon. The pivoting motor 45 pivots,via the pivot shaft 44, the pivot arm 43 about the pivot shaft 44whereby the substrate holder 14 is pivoted horizontally to a positionright above the electrode holder 12. Thereafter, the vertical movementmotor 47 rotates the ball screw 46 to lower the pivot shaft 44. Thepivot shaft 44 lowers the substrate holder 14 via the pivot arm 43towards the electrode holder 12 so as to bring the lower surface WA ofthe substrate W into contact with the upper surface 18B of theprocessing electrode 18.

The electrolytic solution 49 is supplied by the not-shown electrolyticsolution supply means to the electrolytic solution supply inlet 28. Theelectrolytic solution 49 passes through the hollow portion 42C, thehollow passage 20, the through-hole 19, the depression 17 and thethrough-holes 29, and is supplied from the entire surface 18B, facingthe substrate W, of the processing electrode 18 to the ion exchanger 35.The electrolytic solution 49 is then supplied from the upper surface 35Bof the ion exchanger 35 to the entire lower surface WA of the substrateW. Next, a voltage is applied from each of the power sources 23 tobetween each of the processing electrode parts 18-1 through 18-7 and thesubstrate W, respectively.

The electrode holder 12 is rotated at a given angular speed via theelectrode-rotating shaft 13 by the actuation of the hollow motor 42, andthe substrate holder 14 is rotated at a given angular speed via thesubstrate-rotating shaft 15 by the actuation of the hollow motor 41,while electrolytic processing of the substrate surface WA is carriedout.

The processing electrode 18 is disposed opposite to the lower surface WAof the substrate W. Further, the ion exchanger 35 is disposed betweenthe processing electrode 18 and the substrate W. Accordingly, when waterhaving an electric conductivity of not more than 500 μS/cm, pure wateror ultrapure water, for example, is used as the electrolytic solution49, water molecules dissociate into hydroxide ions (OH⁻) and hydrogenions (H⁺). The density of hydroxide ions at the lower surface WA of thesubstrate W is increased by the flow of the electrolytic solution 49 andby the electric field between the substrate W and the processingelectrode 18, whereby a reaction occurs between e.g. the atoms of aplated film (not shown) and hydroxide ions. The reaction products aredissolved in the electrolytic solution 49, and are removed from thesubstrate W by the flow of electrolytic solution 49 along the lowersurface WA of the substrate W. Electrolytic processing of the lowersurface WA of the substrate W is thus effected.

It is desirable to use as the electrolytic solution 49 a liquid obtainedby adding an additive, such as a surfactant, to water, pure water orultrapure water, having an electric conductivity of not more than 500μS/cm, preferably not more than 50 μS/cm, more preferably not more than10 μS/cm, especially preferably not more than 0.1 μS/cm. The use of sucha liquid makes it possible to carry out a clean processing withoutleaving impurities on the substrate surface WA, whereby a step ofcleaning the substrate W after the electrolytic processing can besimplified. The electrolytic conductivity of the liquid herein refers tothe corresponding value at 25° C., 1 atm.

A description will now be made of control of the voltage suppliedbetween the processing electrode 18 and the substrate W. As describedabove, at least one of the voltage and the electric current appliedbetween each of the processing electrode parts 18-1 through 18-7 and thesubstrate W is controlled independently, making it possible to equalizethe electric field intensity over the entire surface of the processingelectrode 18, and apply respectively different voltages to therespective processing electrode parts 18-1 through 18-7 so that the sameintensity of electric current can flow over the entire surface of theprocessing electrode 18. This can equalize the supply of hydroxide ionsto the lower surface WA of the substrate W to equalize the hydroxide ionconcentrate over the entire lower surface WA, thereby equalizing theprocessing rate over the lower surface WA of the substrate W. Further,by effecting such control that a processing rate distribution suited forthe configuration (thickness distribution) of the to-be-processedsurface before processing is obtained, evenness of the processed surfacecan be improved over the entire lower surface WA of the substrate W.

Further, unevenness of the substrate surface after processing, whichwould be caused by unevenness of current value due to the shape of theprocessing electrode 18 or to the influence of gas bubbles generatedduring processing, can be reduced.

When the to-be-processed material of the substrate W is copper,molybdenum or iron, for example, a voltage is applied so that theprocessing electrode 18 becomes a cathode and the substrate W becomes ananode. When the to-be-processed material is aluminum or silicon, on theother hand, a voltage is applied so that the processing electrode 18becomes an anode and the substrate W becomes a cathode.

As shown in FIG. 9, the electrolytic processing apparatus 50 may beprovided with a regeneration section 71 for regenerating the ionexchanger 35 (see FIG. 7), disposed beside the substrate holder 12 forholding the substrate W (shown with the broken line). The regenerationsection 71 includes a regeneration tank 72 provided with a not-shown ionexchanger for regeneration. The regeneration tank 72 is connected to anot-shown electrode. Further, the regeneration tank 72 is so designedthat the electrolytic solution 49 (see FIG. 7) can be supplied to theupper surface of the ion exchanger upwardly from under the ionexchanger. In operation, the pivot arm 43 is pivoted to move theelectrode holder 12 to right above the regeneration tank 72, and is thenlowered to bring the ion exchanger 35 close to or into contact with theion exchanger for regeneration. In FIG. 9, the pivot arm 43 and thesubstrate holder 12 in the regeneration position are shown with thechain lines.

A positive potential, for example, is applied to the processingelectrode 18 (see FIG. 7) and a negative potential is applied to the ionexchanger 35 to be regenerated so as to promote detachment of extraneousmatter, such as copper, molybdenum or ion, adhering to the ion exchanger35, thereby regenerating the ion exchanger 35. The regenerated ionexchanger 35 may be rinsed e.g. with pure water.

FIG. 10 is a partly sectional block diagram schematically showing anelectrolytic processing apparatus 50 a according to a second embodimentof the present invention.

According to the electrolytic processing apparatus 50 a, a processingelectrode 118 and a feeding electrode 136 are held by an electrodeholder 112. The processing electrode 118 is divided into five processingelectrode parts 118-1 through 118-5 by ring-shaped four insulators 140-1through 140-4, and is peripherally surrounded by a ring-shaped insulator140-5. In the processing electrode parts 118-1 through 118-5, a numberof through-holes 129 are formed as a fluid supply section for supplyingan electrolytic solution 102 to the substrate W (one through-hole 129for each of the processing electrode parts 118-1 through 118-5 isdepicted in FIG. 10).

The outermost insulator 140-5 is surrounded by a ring-shaped feedingelectrode 136. The whole processing electrode parts 118-1 through 118-5,the whole insulators 140-1 through 140-5 and the feeding electrode 136are formed integrally in a disk shape (see FIG. 11).

According to the electrolytic processing apparatus 50 a of thisembodiment, a wire 124 connected to the processing electrode 118 and awire 125 connected to the feeding electrode 136 both pass through adepression 117 formed in the electrode holder 112, a through-hole 119, ahollow passage 120 as a fluid supply section, formed in anelectrode-rotating shaft 113 mounted to the electrode holder 112, ahollow portion 142C of a hollow motor 142 mounted to the lower end 113Aof the electrode-rotating shaft 113, and through a slip ring 126 mountedto the lower end 142A of the hollow motor 142, and are connected to apower source 123. The slip ring 126 has an electrolytic solution supplyinlet 128 to which the electrolytic solution 102 is supplied by anot-shown electrolytic solution supply means.

In FIG. 10, the wire 124 connected to the processing electrode 118 andthe wire 125 connected to the feeding electrode 136 are respectivelydrawn as a single wire, and a single power source 123 is drawn. As shownin FIG. 12, however, the wire 124 is in fact composed of five wires, andeach wire 124 is connected to each of the processing electrode parts118-1 through 118-5. The wire 125 is also composed of five wires, andthe respective wires 125 are connected to the feeding electrode 136, theconnections being distant from each other. Further, a pair of the wires124, 125 is connected to separate (five) power sources 123 to formseparate circuits.

In a substrate holder 114, there is not formed a depression that formsan interspace between the substrate holder and the substrate W nor athrough-hole. A substrate-rotating shaft 115 does not have a hollowpassage, and a pivot arm 143 and a pivot shaft 144 each do not have ahollow portion. Further, no slip ring is attached to the pivot arm 143.Further, according to this embodiment, since one feeding electrode 136is employed, it is sufficient for an ion exchange 135 to be in contactwith at least part of the ring-shaped feeding electrode 136.

Though the electrolytic processing apparatus 50 a of this embodimentdiffers from the electrolytic processing apparatus 50 of the firstembodiment in the above-described respects, the other construction isthe same.

The operation of the electrolytic processing apparatus 50 a of thisembodiment is the same as the electrolytic processing apparatus 50 ofthe first embodiment, except that the substrate W does not function as afeeding electrode and, in addition, the provision of the ring-shapedfeeding electrode 136 outside of the processing electrode 118 and thedivision of the processing electrode 118 by the ring-shaped insulators140-1 through 140-5 operate differently.

According to the electrolytic processing apparatus 50 a of thisembodiment, the processing electrode 118 is composed of the processingelectrode parts 118-1 through 118-5 that are divided by the ring-shapedinsulators 140-1 through 140-5, each of the processing electrode parts118-1 through 118-5 and the feeding electrode 136 forms a separatecircuit, and at least one of the voltage and the electric currentsupplied between each of the processing electrode parts 118-1 through118-5 and the feeding electrode 136 is controlled separately.Accordingly, voltages can be applied between the processing electrodes118-1 through 118-5 and the feeding electrode 136 in such a state thatthe same intensity of electric current can flow over the entire surfaceof the processing electrode 118. This can equalize the supply ofhydroxide ions to the lower surface WA of the substrate W to equalizethe hydroxide ion concentration over the entire lower surface WA,thereby equalizing the processing rate over the entire lower surface WAof the substrate W. Since the substrate W is not utilized as a feedingelectrode and the feeding electrode 136 is provided according to thisembodiment, electrolytic processing of a conductive material in thesurface of the substrate W can be carried out not only when the surfaceof the substrate W is formed of a conductive material, but when thesubstrate W is formed of a non-conductive material.

In the electrolytic processing apparatus 50 a of this embodiment,instead of the feeding electrode 136, the following feeding electrode236 may be employed:

As shown in FIG. 13, the feeding electrode 236 is provided with fiveinsulators 251-1 through 251-5, so that it is divided into five feedingelectrode parts 236-1 through 236-5. The feeding electrode parts 236-1through 236-5 are each connected to a wire 225 (see FIG. 14),respectively.

As shown in FIG. 14, the respective wires 224 connected to therespective processing electrode parts 218-1 through 218-5 and therespective wires 225 connected to the respective feeding electrode parts236-1 through 236-5 are connected to separate power sources 223 to formseparate circuits.

In the case of this embodiment, since the feeding electrode 236 areseparated by the insulators 251-1 through 251-5, it is necessary for thesubstrate W (not shown in FIG. 14) to be in contact with the entiresurface of the processing electrode 218 and of the feeding electrode236.

In the above-described first to third embodiments, the center of thesubstrate meets the center of the processing electrode, and thesubstrate and the processing electrode, having the same size, arerotated in opposite directions. This facilitates zone control. On theother hand, however, the shape of the electrode or of the ion exchangercan be transferred to the to-be-processed surface of the substrate,resulting in formation of a rut-like pattern on the substrate surface.It is therefore preferred to carry out, in addition to rotation, acertain degree of other movement such as a scroll movement (orbitalmovement without self-rotation) or a small-distance reciprocatingmovement. The term “zone” herein refers to a partial region of thesurface of a substrate, and the term “zone control” refers to control ofthe processing rates at various zones effected by independent control ofat least one of the voltage and the electric current supplied betweeneach of the processing electrode parts and the feeding electrode (orfeeding electrode parts) to obtain a desired processing ratedistribution.

In the above-described second and third embodiments, as in the cases ofthe processing electrodes 118 (see FIG. 11), 218 (see FIG. 13), the ionexchangers 135, 235 may be divided by ring-shaped insulators 130-1through 130-5, 230-1 through 230-5, having the same plan shape as theinsulators 140-1 through 140-5 (see FIG. 13), 240-1 through 240-5 (seeFIG. 13), into a central circular part and outer ring-shaped parts, asshown in FIG. 15. Some of the five insulators 130-1 through 130-5, 230-1through 230-5 may be omitted, thereby reducing the number of dividedparts of the ion exchangers 135, 235 from 6 to 1-5. It is of coursepossible to divide the ion exchangers 135, 235 into 7 or more parts.

In FIGS. 11 through 14, a depiction of a through-hole formed in the ionexchanger is omitted.

A substrate processing apparatus 260, which is provided with theabove-described electrolytic processing apparatus 50, will now bedescribed with reference to FIG. 16, taking the electrolytic processingapparatus 50 as an example and referring to FIG. 7 as necessary. Asshown in FIG. 16, the substrate processing apparatus 260 includes a pairof loading/unloading sections 262 as a carry-in-and-out section forcarrying in and out a substrate W, a reversing machine 264 for reversingthe substrate W, and the electrolytic processing apparatus 50, which aredisposed in series. A transfer robot 268 a as a transfer device movesparallel with these equipments for transfer and delivery of thesubstrate W.

The substrate processing apparatus 260 is also provided with acontroller 266 which, when carrying out electrolytic processing by theelectrolytic processing apparatus 50, monitors the voltage appliedbetween the processing electrode 18 (see FIG. 7) and the substrate(feeding electrode) W (see FIG. 7) or the electric current flowingtherebetween, and controls at least one of the voltage and the electriccurrent between each of the processing electrode parts 18-1 through 18-7(see FIG. 7) and the substrate (feeding electrode) w independently. Thesubstrate processing apparatus 260, with the provision of theabove-described electrolytic processing apparatus 50, can equalize theprocessing rate in electrolytic processing of the substrate W over theentire lower surface WA (see FIG. 7) and produce a processed substrate Wwith a highly flat (within substrate uniformity) surface WA.

According to the embodiments, as described hereinabove, a processingelectrode and a feeding electrode are provided, at least one of theprocessing electrode and the feeding electrode is electrically dividedinto a plurality of parts, and, for each of the divided electrode parts,at least one of the voltage and the electric current can be controlledindependently. Accordingly, the present invention makes it possible toimprove evenness of the electric field intensity over the entireto-be-processed surface of a workpiece, thereby improving evenness ofthe processing rate, or control the processing rate at an optimumprocessing rate distribution for the configuration of theto-be-processed surface before processing, thereby improving evenness ofthe surface after processing.

FIG. 17 is a vertical sectional view schematically showing theelectrolytic processing apparatus 334 according to a fourth embodimentof the present invention. As shown in FIG. 17, the electrolyticprocessing apparatus 334 includes a pivot arm 340 that can pivothorizontally and move vertically, a substrate holder 342, supported atthe free end of the pivot arm 340, for attracting and holding thesubstrate W with its front surface facing downward (face-down), adisk-shaped electrode section 344 positioned beneath the substrateholder 342, and a power source 346 connected to the electrode section344. In this embodiment, the size of the electrode section 344 isdesigned to have a slightly larger diameter than the diameter of thesubstrate W to be held by the substrate holder 342.

The pivot arm 340, which pivots horizontally by the actuation of a motor348 for pivoting, is connected to the upper end of a pivot shaft 350.The pivot shaft 350, which moves up and down integrated with the pivotarm 340 via a ball screw 352 by the actuation of a motor 354 forvertical movement, is engaged with the ball screw 352 that extendsvertically.

The substrate holder 342 is connected to a rotating motor 356 as a firstdrive element that is allowed to move the substrate W held by asubstrate holder 342 and the electrode section 344 relatively to eachother. The substrate holder 342 is rotated by the actuation of therotating motor 356. The pivot arm 340 can pivot horizontally and movevertically, as described above, the substrate holder 342 can pivothorizontally and move vertically integrated with the pivot arm 340.

The hollow motor 360 as a second drive element that is allowed to movethe substrate W and the electrode section 344 relatively to each otheris disposed below the electrode section 344. A drive end 364 is formedat the upper end portion of the main shaft 362 and arrangedeccentrically position to the center of the main shaft 362. Theelectrode section 344 is rotatably coupled to the drive end 364 via abearing (not shown) at the center portion thereof. Three or more ofrotation-prevention mechanisms are provided in the circumferentialdirection between the electrode section 344 and the hollow motor 360.

FIG. 18A is a plan view showing the rotation-prevention mechanisms ofthis embodiment, and FIG. 18B is a cross-sectional view taken along theline A-A of FIG. 18A. As shown in FIGS. 18A and 18B, three or more (fourin FIG. 18A) of rotation-prevention mechanisms 366 are provided in thecircumferential direction between the electrode section 344 and thehollow motor 360. As shown in FIG. 18B, a plurality of depressions 368,370 are formed at equal intervals in the circumferential direction atthe corresponding positions in the upper surface of the hollow motor 360and in the lower surface of the electrode section 344. Bearings 372, 374are fixed in each depression 368, 370, respectively. A connecting member380, which has two shafts 376, 378 that are eccentric to each other byeccentricity “e”, is coupled to each pair of the bearings 372, 374 byinserting the respective ends of the shafts 376, 378 into the bearings372, 374. The eccentricity of the drive end 364 against to the center ofthe main shaft 362 is also “e”. Accordingly, the electrode section 344is allowed to make a revolutionary movement with the distance betweenthe center of the main shaft 362 and the drive end 364 as radius “e”,without rotation about its own axis, i.e. the so-called scroll movement(translational rotation movement) by the actuation of the hollow motor360.

As shown in FIG. 17, a through-hole 344 a as a pure water supply sectionfor supplying pure water, preferably ultrapure water, is formed in thecentral portion of the electrode section 344. The through-hole 344 a isconnected to a pure water supply pipe 382 that vertically extends insidethe hollow motor 360, via a through hole 362 a formed in the main shaft362. Thus, pure water or ultrapure water is supplied to the uppersurface of the electrode section 344.

FIG. 19 is a vertical sectional view schematically showing the substrateholder 342 and the electrode section 344, and FIG. 20 is a plan viewshowing the relationship between the substrate holder 342 and theelectrode section 344. In FIG. 20, the substrate holder 342 is shownwith the broken lines. As shown in FIGS. 19 and 20, the electrodesection 344 includes a disk-shaped processing electrode 384, aring-shaped feeding electrode 386 that surrounds the processingelectrode 384, and a ring-shaped insulator 388 that separates theprocessing electrode 384 from the feeding electrode 386. The uppersurface of the processing electrode 384 is covered with an ion exchanger390 and the upper surface of the feeding electrode 386 is covered withan ion exchanger 392, respectively. The ion exchangers 390, 392 areseparated from each other by the insulator 388.

According to this embodiment, the processing electrode 384 is connectedto the cathode of the power source 346, and the feeding electrode 386 isconnected to the anode of the power source 346. Depending upon amaterial to be processed, the electrode connected to the cathode of thepower source 346 can be a feeding electrode and the electrode connectedto the anode of the power source 346 can be a processing electrode. Morespecifically, when the material to be processed is copper, molybdenum,iron or the like, electrolytic processing proceeds on the cathode side,and therefore the electrode connected to the cathode of the power source346 should be the processing electrode and the electrode connected tothe anode of the power source 346 should be the feeding electrode. Inthe case of aluminum, silicon or the like, on the other hand,electrolytic processing proceeds on the anode side. Accordingly, theelectrode connected to the anode of the power source 346 should be theprocessing electrode and the electrode connected to the cathode of thepower source 346 should be the feeding electrode.

As shown in FIG. 19, the substrate holder 342 includes a shaft 394connected to a rotating motor 356, a body 396 coupled to the shaft 394,an annular dummy member 398 disposed outside of the periphery of thesubstrate W, and an annular buffering member (cushioning material) 399disposed between the dummy member 398 and the substrate W. At least thefront surface of the dummy member 398 is formed of an electricallyconductive material. The apparatus is so designed that when thesubstrate W is rotated and, at the same time, the electrode section 386is allowed to make a scroll movement while the substrate W is closed toor in contact with the ion exchangers 390, 392, part of the dummy member398 is always positioned above the feeding electrode 386 and theprocessing electrode 384.

As a material for the conductive portion of the dummy member 398, it ispossible to use, besides the conventional metals and metal compounds,carbon, relatively inactive noble metals, conductive oxides orconductive ceramics. Electrochemically inactive materials are preferred.When an electrochemically inactive material is employed for the dummymember 398, the dummy member 398 is not processed, and therefore thelife of the dummy member 398 can be prolonged. It is also possible touse as the dummy member 398 an insulating substrate, e.g. of a resin,coated with a conductive material, for example, a substrate whosesurface is covered with a hardly oxidative material such as platinum orwith a conductive oxide such as iridium oxide. Such a dummy member canbe produced by attaching platinum or iridium to the surface of e.g. atitanium substrate by coating or plating, and then carrying outsintering at a high temperature to stabilize and strengthen the product.Ceramics products, in general, are obtained by heat treatment of aninorganic starting material, and ceramics products with a variety ofproperties are now commercially produced using various materialsincluding oxides, carbides and nitrides of metals and nonmetals, amongwhich are ceramics having an electric conductivity.

The buffering member 399, disposed between the dummy member 398 and thesubstrate W, is formed of a material having a lower hardness than thedummy member 398, and can absorb a shock to the substrate W. Though thebuffering member 399 may be an insulator, it is preferably an electricconductor.

Next, substrate processing (electrolytic processing) by using theelectrolytic processing apparatus 334 of this embodiment instead of theelectrolytic processing apparatus 50 of the substrate processingapparatus 260 shown in FIG. 16 will be described. First, a substrate W,e.g. a substrate W as shown in FIG. 1B which has in its surface a copperfilm 6 as a conductor film (portion to be processed), is taken by thetransfer robot 268 a out of the cassette housing substrates and set inthe loading/unloading unit 262. If necessary, the substrate W istransferred to the reversing machine 264 by the transfer robot 268 a toreverse the substrate so that the front surface of the substrate Whaving the conductor film (copper film 6) faces downward.

The transfer robot 268 a receives the reversed substrate W, andtransfers it to the electrolytic processing apparatus 334. The substrateW is then attracted and held by the substrate holder 342. The substrateholder 342, which holds the substrate W, is moved by pivoting of thepivot arm 340 to a processing position right above the electrode section344. The substrate holder 342 is then lowered by the actuation of themotor 354 for vertical movement, so that the substrate W held by thesubstrate holder 342 and the dummy member 398 contacts or gets close tothe surfaces of the ion exchangers 390, 392 of the electrode section344. Then, the rotating motor (first drive element) 356 is actuated torotate the substrate W, at the same time, the hollow motor (second driveelement) 360 is actuated to make a scroll movement of the electrodesection 344, while supplying pure water or ultrapure water to betweenthe substrate W and ion exchangers 390, 392, through the through-hole344 a of the electrode section 344.

A given voltage is applied from the power source 346 to between theprocessing electrode 384 and the feeding electrode 386 to carry outelectrolytic processing of the conductive film (copper film 6) in thesurface of the substrate W at the processing electrode (cathode) 384through the action of hydrogen ions or hydroxide ions generated with theaid of the ion exchangers 390, 392. The processing progresses at theportion of the substrate facing the processing electrode 384. However,by allowing the substrate Wand the processing electrode 384 to make arelative movement as described above, the entire surface of thesubstrate W can be processed. According to this embodiment, with theprovision of the conductive dummy member 398 outside of the periphery ofthe substrate W, as shown in FIG. 20, the area of the processingelectrode 384 facing the substrate W and the dummy member 398, i.e. theface-to-face area, is always constant (shaded area S₄) regardless of therelative movement of the substrate W and the processing electrode 384.Accordingly, the current density can be made always constant even with aconstant current value, making it possible to equalize the processingrate over the entire surface of the substrate W and carry out a uniformprocessing stably. Further, since concentration of the electric fieldintensity occurs at the dummy member 398, the electric field intensityat the end portion of the substrate W can be made the same as in theother portion. Accordingly, as shown in FIG. 6C, the electric fieldintensity can be made even over the entire surface of the workpiece 60,making it possible to equalize the processing rate over the entiresurface of the workpiece 60 and carry out a uniform processing stably.By forming the dummy member 398 by an electrochemically inactivematerial, the dummy member 398 can be prevented from being processed,together with the substrate W, during electrolytic processing.

The controller 266 (see FIG. 16) monitors the voltage applied betweenthe processing electrode and the feeding electrode or the electriccurrent flowing therebetween to detect the end point (terminal ofprocessing). It is noted in this connection that in electrolyticprocessing an electric current (applied voltage) varies, depending uponthe material to be processed, even with the same voltage (electriccurrent). For example, as shown in FIG. 21A, when an electric current ismonitored in electrolytic processing of the surface of a substrate W towhich a film of material B and a film of material A are laminated inthis order, a constant electric current is observed during theprocessing of material A, but it changes upon the shift to theprocessing of the different material B. Likewise, as shown in FIG. 21B,though a constant voltage is applied between the processing electrodeand the feeding electrode during the processing of material A, thevoltage applied changes upon the shift to the processing of thedifferent material B. FIG. 21A illustrates, by way of example, a case inwhich an electric current is harder to flow in electrolytic processingof material B compared to electrolytic processing of material A, andFIG. 21B illustrates a case in which the applied voltage becomes higherin electrolytic processing of material B compared to electrolyticprocessing of material A. As will be appreciated from theabove-described example, the monitoring of changes in electric currentor in voltage can surely detect the end point.

Though this embodiment shows the case where the controller 266 monitorsthe voltage applied between the processing electrode and the feedingelectrode, or the electric current flowing therebetween to detect theend point of processing, it is also possible to allow the controller 266to monitor a change in the state of the substrate being processed todetect an arbitrarily set end point of processing. In this case, “theend point of processing” refers to a point at which a desiredprocessingamount is attained for a specified region in a surface to beprocessed, or a point at which an amount corresponding to a desiredprocessing amount is attained in terms of a parameter correlated with aprocessing amount for a specified region in a surface to be processed.By thus arbitrarily setting and detecting the end point of processingeven in the middle of processing, it becomes possible to conduct amulti-step electrolytic processing.

For example, the processing amount may be determined by detecting thechange of frictional force due to a difference of friction coefficientproduced when the processing surface reaches a different material, orthe change of frictional force produced by removal of irregularities inthe surface of the substrate. The end point of processing may bedetected based on the processing amount thus determined. Duringelectrolytic processing, heat is generated by the electric resistance ofthe to-be-processed surface, or by collision between water molecules andions that migrate in the liquid (pure water) between the processingsurface and the to-be-processed surface. When processing e.g. a copperfilm deposited on the surface of a substrate under a controlled constantvoltage, with the progress of electrolytic processing and a barrierlayer and an insulating film becoming exposed, the electric resistanceincreases and the current value decreases, and the heat value graduallydecreases. Accordingly, the processing amount may be determined bydetecting the change of the heat value. The end point of processing maytherefore be detected. Alternatively, the film thickness of ato-be-processed film on a substrate may be determined by detecting thechange in the intensity of reflected light due to a difference ofreflectance produced when the processing surface reaches a differentmaterial. The end point of processing may be detected based on the filmthickness thus determined. The film thickness of a to-be-processed filmon a substrate may also be determined by generating an eddy currentwithin a to-be-processed conductive film, e.g. a copper film, andmonitoring the eddy current flowing within the substrate to detectchange of e.g. the frequency. The end point of processing may thus bedetected. Further, in electrolytic processing, the processing ratedepends on the value of the electric current flowing between theprocessing electrode and the feeding electrode, and the processingamount is proportional to the quantity of electricity, determined as theproduct of the current value and the processing time. Accordingly, theprocessing amount may be determined by integrating the quantity ofelectricity, determined as the product of the current value and theprocessing time, and detecting that the integrated value reaches apredetermined value. The end point of processing may thus be detected.

After completion of the electrolytic processing, the power source 346 isdisconnected, and the rotation of the substrate holder 342 and thescroll movement of the electrode section 344 are stopped. Thereafter,the substrate holder 342 is raised, and substrate W is transferred tothe transfer robot 268 a after pivoting the pivot arm 340. The transferrobot 268 a takes the substrate W from the substrate holder 344 and, ifnecessary, transfers the substrate W to the reversing machine 264 forreversing it, and then returns the substrate W to the cassette in theloading/unloading unit 262.

Pure water, which is supplied between the substrate W and the ionexchangers 390, 392 during electrolytic processing, herein refers to awater having an electric conductivity of not more than 10 μS/cm, andultrapure water refers to a water having an electric conductivity of notmore than 0.1 μS/cm. The use of pure water or ultrapure water containingno electrolyte upon electrolytic processing can prevent impurities suchas an electrolyte from adhering to and remaining on the surface of thesubstrate W. Further, copper ions or the like dissolved duringelectrolytic processing are immediately caught by the ion exchanger 390,392 through the ion-exchange reaction. This can prevent the dissolvedcopper ions or the like from re-precipitating on the other portions ofthe substrate W, or from being oxidized to become fine particles whichcontaminate the surface of the substrate W.

It is possible to use, instead of pure water or ultrapure water, aliquid having an electric conductivity of not more than 500 μS/cm, forexample, an electrolytic solution obtained by adding an electrolyte topure water or ultrapure water. The use of such an electrolytic solutioncan further lower the electric resistance and reduce the powerconsumption. A solution of a neutral salt such as NaCl or Na₂SO₄, asolution of an acid such as HCl or H₂SO₄, or a solution of an alkalisuch as ammonia, may be used as the electrolytic solution, and thesesolutions may be selectively used according to the properties of theworkpiece.

Further, it is also possible to use, instead of pure water or ultrapurewater, a liquid obtained by adding a surfactant or the like to purewater or ultrapure water, and having an electric conductivity of notmore than 500 μS/cm, preferably not more than 50 μS/cm, more preferablynot more than 0.1 μS/cm (resistivity of not less than 10 MΩ·cm). Due tothe presence of a surfactant in pure water or ultrapure water, theliquid can form a layer, which functions to inhibit ion migrationevenly, at the interface between the substrate W and the ion exchangers390, 392, thereby moderating concentration of ion exchange (metaldissolution) to enhance the flatness of the processed surface. Thesurfactant concentration is desirably not more than 100 ppm. When thevalue of the electric conductivity is too high, the current efficiencyis lowered and the processing rate is decreased. The use of the liquidhaving an electric conductivity of not more than 500 μS/cm, preferablynot more than 50 μS/cm, more preferably not more than 0.1 μS/cm, canattain a desired processing rate.

The ion exchangers 390, 392 of the electrode section 344 may be composedof a nonwoven fabric which has an anion-exchange group or acation-exchange group. A cation exchanger preferably carries a stronglyacidic cation-exchange group (sulfonic acid group); however, a cationexchanger carrying a weakly acidic cation-exchange group (carboxylgroup) may also be used. Though an anion exchanger preferably carries astrongly basic anion-exchange group (quaternary ammonium group), ananion exchanger carrying a weakly basic anion-exchange group (tertiaryor lower amino group) may also be used.

The nonwoven fabric carrying a strongly basic anion-exchange group canbe prepared by, for example, the following method: A polyolefin nonwovenfabric having a fiber diameter of 20-50 μm and a porosity of about 90%is subjected to the so-called radiation graft polymerization, comprisingγ-ray irradiation onto the nonwoven fabric and the subsequent graftpolymerization, thereby introducing graft chains; and the graft chainsthus introduced are then aminated to introduce quaternary ammoniumgroups thereinto. The capacity of the ion-exchange groups introduced canbe determined by the amount of the graft chains introduced. The graftpolymerization may be conducted by the use of a monomer such as acrylicacid, styrene, glicidyl methacrylate, sodium styrenesulfonate orchloromethylstyrene. The amount of the graft chains can be controlled byadjusting the monomer concentration, the reaction temperature and thereaction time. Thus, the degree of grafting, i.e. the ratio of theweight of the nonwoven fabric after graft polymerization to the weightof the nonwoven fabric before graft polymerization, can be made 500% atits maximum. Consequently, the capacity of the ion-exchange groupsintroduced after graft polymerization can be made 5 meq/g at itsmaximum.

The nonwoven fabric carrying a strongly acidic cation-exchange group canbe prepared by the following method: As in the case of the nonwovenfabric carrying a strongly basic anion-exchange group, a polyolefinnonwoven fabric having a fiber diameter of 20-50 μm and a porosity ofabout 90% is subjected to the so-called radiation graft polymerizationcomprising γ-ray irradiation onto the nonwoven fabric and the subsequentgraft polymerization, thereby introducing graft chains; and the graftchains thus introduced are then treated with a heated sulfuric acid tointroduce sulfonic acid groups thereinto. If the graft chains aretreated with a heated phosphoric acid, phosphate groups can beintroduced. The degree of grafting can reach 500% at its maximum, andthe capacity of the ion-exchange groups thus introduced after graftpolymerization can reach 5 meq/g at its maximum.

The base material of the ion exchangers 390, 392 may be a polyolefinsuch as polyethylene or polypropylene, or any other organic polymer.Further, besides the form of a nonwoven fabric, the ion-exchanger may bein the form of a woven fabric, a sheet, a porous material, net or shortfibers, etc. When polyethylene or polypropylene is used as the basematerial, graft polymerization can be effected by first irradiatingradioactive rays (γ-rays or electron beam) onto the base material(pre-irradiation) to thereby generate a radical, and then reacting theradical with a monomer, whereby uniform graft chains with few impuritiescan be obtained. When an organic polymer other than polyolefin is usedas the base material, on the other hand, radical polymerization can beeffected by impregnating the base material with a monomer andirradiating radioactive rays (γ-rays, electron beam or UV-rays) onto thebase material (simultaneous irradiation). Though this method fails toprovide uniform graft chains, it is applicable to a wide variety of basematerials.

By using a nonwoven fabric having an anion-exchange group or acation-exchange group as the ion exchangers 390, 392, it becomespossible that pure water or ultrapure water, or a liquid such as anelectrolytic solution can freely move within the nonwoven fabric andeasily arrive at the active points in the nonwoven fabric having acatalytic activity for water dissociation, so that many water moleculesare dissociated into hydrogen ions and hydroxide ions. Further, by themovement of pure water or ultrapure water, or a liquid such as anelectrolytic solution, the hydroxide ions produced by the waterdissociation can be efficiently carried to the surface of the processingelectrodes 384, whereby a high electric current can be obtained evenwith a low voltage applied.

When the ion exchangers 390, 392 have only one of anion-exchange groupsand cation-exchange groups, a limitation is imposed on electrolyticallyprocessible materials and, in addition, impurities are likely to formdue to the polarity. In order to solve this problem, the anion exchangerand the cation exchanger may be superimposed, or the ion exchangers 390,392 may carry both of an anion-exchange group and a cation-exchangegroup per se, whereby a range of materials to be processed can bebroadened and the formation of impurities can be restrained.

With respect to the electrode, its oxidation or dissolution by theelectrolytic reaction usually is a problem. It is therefore preferred touse as an electrode material carbon, a relatively inactive noble metal,a conductive oxide or a conductive ceramic, as in the case of the dummymember 398. An electrode, when oxidized, increases its electricresistance and incurs a rise of the applied voltage. By protecting thesurface of an electrode with a hardly oxidative material, such asplatinum, or with a conductive oxide, such as iridium oxide, a lowing ofthe conductivity due to oxidation of the electrode material can beprevented.

Though, in the above-described embodiment, the dummy member 398 isformed of an electrochemically inactive material, it is possible to formthe dummy member 398 of the same material as the substrate W. When thedummy member 398 is formed of an electrochemically inactive material,depending upon the material of the dummy member 398, a reaction, whichis different from the reaction at the substrate W, can occur at thedummy member 398 whereby uniformity of processing can be impaired. Whenthe dummy member 398 is formed of the same material as the substrate W,on the other hand, the reaction at the dummy member 398 can be made thesame as the reaction at the substrate W, improving uniformity ofprocessing.

FIG. 22 is a perspective view schematically showing an electrolyticprocessing apparatus 334 a according to a fifth embodiment of thepresent invention, and FIG. 23 is a plan view of the electrolyticprocessing apparatus 334 a of FIG. 22. The electrolytic processingapparatus 334 a of this embodiment comprises a substrate holder 342 afor holding a substrate W with its front surface facing upward, acylindrical processing electrode 384 a disposed above the substrateholder 342 a, and two feeding electrodes 386 a (not shown in FIG. 23)disposed above the substrate holder 342 a. The substrate holder 342 aincludes a rectangular dummy member 398 b having a depression 398 a foraccommodating the substrate W, and a buffering member 399 a disposedbetween the dummy member 398 b and the substrate W.

Each feeding electrode 386 a is disposed over the substrate W and thedummy member 398 b, and is in contact with both of the substrate W andthe dummy member 398 b. An ion exchanger is attached to the surface ofthe processing electrode 384 a. The processing electrode 384 a can berotated about a shaft 384 b by means of a not-shown drive section.Further, the processing electrode 384 a can move over the substrate Wwhile it is close to or in contact with the substrate W.

While supplying pure water or ultrapure water from a not-shown purewater supply section to between the substrate W and the ion exchanger ofthe processing electrode 384 a, the processing electrode 384 a, close toor in contact with the substrate W, is moved in one direction by meansof the drive section, thereby carrying out electrolytic processing ofthe surface of the substrate W.

Also in this embodiment, as shown in FIG. 23, the area of the processingelectrode 384 a facing the substrate W and the dummy member 398 b(face-to-face area) is always constant irrespective of the relativemovement of the substrate W and the processing electrode 384 a.Accordingly, the current density can be made always constant even with aconstant current value, making it possible to equalize the processingrate over the entire surface of the substrate W and carry out a uniformprocessing stably.

As described hereinabove, according to the electrolytic processingapparatuses 334, 334 a of the above-described embodiments, unlike a CMPprocessing, electrolytic processing of a workpiece, such as a substrate,can be effected through electrochemical action without causing anyphysical defects in the workpiece that would impair the properties ofthe workpiece. Accordingly, the electrolytic processing apparatuses canomit a CMP treatment entirely or at least reduce a load upon CMP, andcan effectively remove (clean) matter adhering to the surface of theworkpiece such as a substrate. Furthermore, the electrolytic processingof a substrate can be effected even by solely using pure water orultrapure water. This obviates the possibility that impurities such asan electrolyte will adhere to or remain on the surface of the substrate,can simplify a cleaning process after the removal processing, and canremarkably reduce a load upon waste liquid disposal.

FIG. 24 is a vertical sectional view schematically showing theelectrolytic processing apparatus 434 according to a sixth embodiment ofthe present invention. As shown in FIG. 24, the electrolytic processingapparatus 434 includes a pivot arm 440 that can pivot horizontally andmove vertically, a substrate holder 442, supported at the free end ofthe pivot arm 440, for attracting and holding the substrate W with itsfront surface facing downward (face-down), a disk-shaped electrodesection 444 positioned beneath the substrate holder 442, and a powersource 446 connected to the electrode section 444.

The pivot arm 440, which pivots horizontally by the actuation of a motor448 for pivoting, is connected to the upper end of a pivot shaft 450.The pivot shaft 450, which moves up and down integrated with the pivotarm 440 via a ball screw 452 by the actuation of a motor 454 forvertical movement, is engaged with the ball screw 452 that extendsvertically.

The substrate holder 442 is connected to a rotating motor 456 as a firstdrive element that is allowed to move the substrate W held by asubstrate holder 442 and the electrode section 444 relatively to eachother. The substrate holder 442 is rotated by the actuation of the motor456. The pivot arm 440 can swing horizontally and move vertically, asdescribed above, the substrate holder 442 can pivot horizontally andmove vertically integrated with the pivot arm 440.

A hollow motor 460 as a second drive element that is allowed to move thesubstrate W and the electrode section 444 relatively to each other isdisposed below the electrode section 444. A drive end 464 is formed atthe upper end portion of the main shaft 462 and arranged eccentricallyposition to the center of the main shaft 462. The electrode section 444is rotatably coupled to the drive end 464 via a bearing (not shown) atthe center portion thereof. Three or more of rotation-preventionmechanisms are provided in the circumferential direction between theelectrode section 444 and the hollow motor 460. Accordingly, theelectrode section 444 is allowed to make a revolutionary movement withthe distance between the center of the main shaft 462 and the center ofthe drive end 464 as radius “e” (see FIG. 26), without rotation aboutits own axis, i.e. the so-called scroll movement (translational rotationmovement) by the actuation of the hollow motor 460, as with theelectrolytic processing apparatus of the above-described fifthembodiment.

FIG. 25 is a schematic sectional view of the substrate holder 442 andthe electrode section 444, and FIG. 26 is a plan view showing therelationship between the substrate W and the electrode section 444. InFIG. 26, the substrate W is shown with a broken line. As shown in FIGS.25 and 26, the electrode section 444 includes a substantiallydisk-shaped processing electrode 484 having a diameter larger than thatof the substrate W, a plurality of feeding electrodes 486 disposed in aperipheral portion of the processing electrode 484, and insulators 488that separate the processing electrode 484 and the feeding electrodes486. As shown in FIG. 25, the upper surface of the processing electrode484 is covered with an ion exchanger 490, and the upper surfaces of thefeeding electrodes 486 are covered with ion exchangers 492. The ionexchangers 490 and 492 may be formed integrally. The ion exchangers 490,492 are not shown in FIG. 26.

According to this embodiment, it is not possible to supply pure water orultrapure water to the upper surface of the electrode section 444 fromabove the electrode section 444 during electrolytic processing due tothe relationship of the size between the electrode section 444 and thesubstrate holder 442. Thus, as shown in FIGS. 25 and 26, liquid supplyholes 484 a, for supplying pure water or ultrapure water to the uppersurface of the processing electrode 484, are formed in the processingelectrode 484. According to this embodiment, a number of fluid supplyholes 484 a are disposed radially from the center of the processingelectrode 484. The fluid supply holes 484 a are connected to a purewater supply pipe 482 (see FIG. 24) that extends through the hollowportion of the hollow motor 460, so that pure water or ultrapure wateris supplied through the fluid supply holes 484 a to the upper surface ofthe electrode section 444.

In this embodiment, the processing electrode 484 is connected to thecathode of the power source 446, and the feeding electrodes 486 areconnected to the anode of the power source 446. In the case where theto-be-processed material is a conductive oxide such as tin oxide orindium tin oxide (ITO), electrolytic processing is carried out afterreducing the to-be-processed material. More specifically, with referenceto FIG. 24, the electrode connected to the anode of the power source 446serve as a reduction electrode and the electrode connected to thecathode serve as a feeding electrode to effect reduction of theconductive oxide. Subsequently, processing of the reduced conductivematerial is carried out by making the previous feeding electrode serveas the processing electrode. Alternatively, the polarity of thereduction electrode at the time of reduction of the conductive oxide maybe reversed so that the reduction electrode can serve as the processingelectrode. Removal processing of the conductive oxide may also beeffected by making the to-be-processed material serve as a cathode andallowing it to face an anode electrode.

According to the above-described embodiment, though a copper film 6 (seeFIG. 1B) as a conductor film formed in the surface of the substrate isprocessed by electrolytic processing, an unnecessary ruthenium (Ru) filmformed on or adhering to the surface of a substrate may be processed(etched and removed) by electrolytic processing in the same manner bymaking the ruthenium film serve as a anode and the electrode connectedto the cathode serve as a feeding electrode.

During electrolytic processing, the rotating motor 456 (first driveelement) is driven to rotate the substrate W and, at the same, thehollow motor 460 (second drive element) is driven to allow the electrodesection 444 to make a scroll movement about a scroll center “O” (seeFIG. 26). By thus allowing the substrate W held by the substrate holder442 and the processing electrode 484 to make a relative movement withina scroll region S, processing of the whole surface of the substrate W(copper film 6) is effected. The electrolytic processing apparatus 434of this embodiment is so designed that during the relative movement, thecenter of movement (center “O” of scroll movement according to thisembodiment) always lies within the range of substrate W. By thus makingthe diameter of the processing electrode 484 larger than the diameter ofthe substrate W and making the center of movement of the processingelectrode 484 always lie within the range of the substrate W, it becomespossible to best equalize the presence frequency of the processingelectrode 484 over the surface of the substrate W. It also becomespossible to considerably reduce the size of the electrode section 444,leading to a remarkable downsizing and weight saving of the wholeapparatus. It is preferred that the diameter of the processing electrode484 be larger than the sum of the distance of relative movement of thesubstrate W and the processing electrode 484 (scroll radius “e”according to this embodiment) and the diameter of the substrate W, andbe smaller than twice the diameter of the substrate W.

Since the substrate W cannot be processed with the region where thefeeding electrodes 486 are present, the processing rate is low with theperipheral portion in which the feeding electrodes 486 are disposed,compared to the other region. It is therefore preferable to make thearea (region) occupied by the feeding electrodes 486 smaller in order toreduce the influence of the feeding electrodes 486 upon the processingrate. From this viewpoint, according to this embodiment, a plurality offeeding electrodes 486 having a small area are disposed in a peripheralportion of the processing electrode 484, and at least one of the feedingelectrodes 484 is allowed to come close to or into contact with thesubstrate W during the relative movement. This makes it possible toreduce an unprocessible region as compared to the case of disposing aring-shaped feeding electrode in the peripheral portion of theprocessing electrode 484, thereby preventing a peripheral portion of thesubstrate W from remaining unprocessed.

In operation of the electrolytic processing apparatus 434, the motor 454for vertical movement is driven to lower the substrate 442 so as tobring the substrate W held by the substrate holder 442 close to or intocontact with the ion exchangers 490, 492 of the electrode section 444.Thereafter, the rotating motor 456 (first drive element) is driven torotate the substrate W and, at the same time, the hollow motor 460(second drive element) is driven to allow the electrode section 444 tomake a scroll movement about the scroll center “O”, while pure water orultrapure water is supplied from the fluid supply holes 484 a of theprocessing electrode 484 to between the substrate W and the ionexchangers 490, 492.

A given voltage is applied from the power source 446 to between theprocessing electrode 484 and the feeding electrodes 486 to carry outelectrolytic processing of the conductive film (copper film 6) in thesurface of the substrate W at the processing electrode (cathode) 484through the action of hydrogen ions or hydroxide ions generated with theaid of the ion exchangers 490, 492. The processing progresses at theportion of the substrate W facing the processing electrode 484. Asdescribed above, by allowing the substrate W and the processingelectrode 484 to make the relative movement, the entire surface of thesubstrate W can be processed. Also as described above, by making thediameter of the processing electrode 484 larger than the diameter of thesubstrate W and making the center “O” of movement of the processingelectrode 484 always lie within the range of the substrate W, it becomespossible to best equalize the presence frequency of the processingelectrode 484 over the surface of the substrate W. It also becomespossible to considerably reduce the size of the electrode section 444,leading to a remarkable downsizing and weight saving of the wholeapparatus.

As with the above-described fourth embodiment, during the electrolyticprocessing, the voltage applied between the processing electrode and thefeeding electrodes, or the electric current flowing therebetween ismonitored by the controller 266 (see FIG. 16) to detect the end point ofprocessing.

FIG. 27 is cross-sectional view (corresponding to FIG. 25) schematicallyshowing the substrate holder 442 and an electrode section 444 aaccording to another embodiment of the present invention. As with theabove-described embodiment, the electrode section 444 a includes asubstantially disk-shaped processing electrode 484 having a largerdiameter than the diameter of the substrate W, a plurality of feedingelectrodes 486 disposed in a peripheral portion of the processingelectrode 484, and insulators 488 that separate the feeding electrodes486 from the processing electrode 484. According to this embodiment,however, the electrodes do not have an ion exchanger on their surfaces.The other construction is the same as the preceding embodiment. Thus,for example, a plurality of fluid supply holes 484 a, as a fluid supplysection for supplying a processing liquid, such as pure, more preferablyultrapure water or an electrolytic solution, to the processing electrode484, are disposed radially in the processing electrode 484.

Though, in this embodiment, an ion exchanger is not mounted on thesurface of the electrodes, a member other than an ion exchanger may beinterposed between the electrodes and a workpiece. For example, aliquid-permeable member, such as a sponge, may be used so that ions canmove through a liquid between the electrodes and the workpiece.

When a member is not interposed between the electrodes and a workpiece,it is necessary to predetermine the distance between the workpiece andeach electrode and the distance between the processing electrode 484 andeach feeding electrode 486, adjacent to each other with the insulator488 interposed, so that the resistance between the workpiece and eachelectrode may be smaller than the resistance between the processingelectrode 484 and each feeding electrode 486. This allows ions to movepreferentially between the electrodes and the workpiece rather thanbetween the adjacent electrodes, so that the electric current flowspreferentially as follows:

-   -   feeding electrode→workpiece→processing electrode

When etching and removing an unnecessary ruthenium (Ru) film formed onor adhering to the surface of a substrate W by the electrolyticprocessing apparatus of this embodiment, an electrolytic solutioncontaining a halide, for example, is supplied between the processingelectrode 484, feeding electrodes 486 and the ruthenium (Ru) film as theto-be-processed portion of the substrate W. The feeding electrodes 486are connected to the anode of a power source and the processingelectrode 484 is connected to the cathode so that the ruthenium (Ru)film on the surface of the substrate W becomes an anode and theprocessing electrode 484 becomes a cathode, and the electrolyticsolution is supplied between the substrate W and the processingelectrode 484, feeding electrodes 486 to etch and remove theto-be-processed portion facing the processing electrode 484.

With regard to the electrolytic solution, water or an organic solventsuch as an alcohol, acetonitrile, dimethylform amide, dimethylsulfoxide, etc. may be used as a solvent for a halide. An appropriatesolvent may be selected depending on the intended usage of the rutheniumfilm to be processed, the cleaning step necessary after processing, thesurface condition of the ruthenium film, etc. For a substrate for use insemiconductor manufacturing, it is preferred to use pure water, morepreferably ultrapure water, in order to best avoid impuritycontamination of the substrate.

An electrolytic solution of any halide may be employed insofar asetching processing of the ruthenium film can progress through anelectrochemical interaction, and a compound generated duringelectrolytic reacts with ruthenium and the reaction product can bedissolved in the electrolytic solution or volatilized and removed.Specific examples of usable electrolytic solutions may include anaqueous solution of a hydrohalogenic acid such as HCl, HBr or HI, anaqueous solution of a halogen oxo acid such as HClO₃, HBrO₃, HIO₃, HClO,HBrO or HIO, an aqueous solution of a halogen oxo acid salt such asNaClO₃, KClO₃, NaClO or KClO, and an aqueous solution of a neutral saltsuch as NaCl or KCl. An appropriate electrolytic solution may beselected depending on the intended usage of the ruthenium film afterprocessing and the influence of remaining material upon the usage, thethickness of the ruthenium film, the properties of a film underlying theruthenium film, etc.

As with the above-described embodiment, in operation of the electrolyticprocessing apparatus, the substrate W is rotated via the substrateholder 442 in such a state that the substrate W is closed to or contactwith the processing electrode 484 and the feeding electrodes 486, andthe electrode section 444 is made the scroll movement, whereby theruthenium film is etched away by electrochemical action. Further, ahalide generated by electrolysis reacts with the ruthenium, wherebyetching and removal of the ruthenium film progresses. The substratesurface after processing is cleaned by ultrapure water supplied from theultrapure water supply nozzle (not shown).

The halide concentration of the halide-containing electrolytic solutionis generally 1 mg/l to 10 g/l, preferably 100 mg/l to 1 g/l. The type ofhalide, the processing time, the processing area, the distance betweenthe ruthenium film as an anode and the processing electrode as acathode, the electrolytic voltage, etc. may appropriately be determineddepending upon the surface condition of the substrate after electrolyticprocessing, the capacity for waste liquid treatment, etc. For example,the amount of chemical can be reduced by using an electrolytic solutionwith a dilute halide concentration and increasing the electrolysisvoltage. The processing rate can be increased by increasing the halideconcentration of the electrolytic solution.

Though the preceding embodiments employ the electrode sections 444, 444a which include the processing electrode 484 composed of a singlemember, usable electrode sections are not limited to such an electrodesection. For examples, it is possible to use an electrode section 444 bas shown in FIG. 28, which includes processing electrodes 484 b that isdivided into a plurality of parts in a lattice form. It is also possibleto use an electrode section 444 c as shown in FIG. 29, which includesprocessing electrodes 484 c that is divided into a plurality ofring-shaped parts. In these cases, the divided processing electrodeparts may either be electrically integrated, or electrically separatedby insulators. In the case where the processing electrode iselectrically separated, it is not easy to equalize the processing ratesat the respective divided parts. When the variation of processing ratebetween the divided parts is taken into consideration, it is preferredto use a processing electrode composed of a single member.

As described above, in the electrode sections 444, 444 a having theprocessing electrode 484 composed of a single member, since thesubstrate W cannot be processed with the region where the feedingelectrodes 486 are present, the processing rate is low with theperipheral portion in which the feeding electrodes 486 are disposed,compared to the other region. The processing rate of a peripheralportion of the substrate W can be controlled by adjusting a cut-offwidth w and a cut-off length L (see FIG. 26) in the peripheral portionof the processing electrode 484. Further, the use of an electrodesection 444 d as shown in FIG. 30, in which the processing electrode isdivided by insulators 489 into an outer processing electrode 484 ddefined by the region where the feeding electrodes 486 have an influenceon the processing rate, i.e. the peripheral portion in which the feedingelectrodes 486 are disposed, and an inner processing electrode 484 edefined by the region where the feeding electrodes have no influence onthe processing rate, i.e. the region on the inner side of the outerprocessing electrode 484 d, can realize a uniform processing rate overthe entire surface of the processing electrode. Thus, in view of theinfluence of the presence of feeding electrodes 486, the voltage orelectric current applied from the power source 446 to each processingelectrode 484 d, 484 e may be adjusted so as to make the processing rateat the outer processing electrode 484 d higher than the processing rateat the inner processing electrode 484 e, thereby realizing a uniformprocessing rate over the entire surface of the processing electrode.

Though, in the above-described embodiment, the electrode section 444 isallowed to make a scroll movement while the substrate W is rotated, anyother manner of relative movement may be employed insofar as it can movethe processing electrode 484 and the substrate W relatively. Forexample, it is possible to rotate the electrode section 444 and thesubstrate W in the opposite directions. In this case, the center ofrotation corresponds to the center of movement of the processingelectrode. Further, though in the above-described embodiment thesubstrate W is attracted and held with its surface facing downward bythe substrate holder 442, the substrate W may be held in other manner,e.g. with its surface facing upward.

As described hereinabove, electrolytic processing apparatus 434according to this embodiment, a workpiece, such as a substrate, can beeffected through electrochemical action, in the place of CMP treatment,for example, without causing any physical defects in the workpiece thatwould impair the properties of the workpiece. Accordingly, the presentinvention can omit a CMP treatment entirely or at least reduce a loadupon CMP, and can effectively remove (clean) matter adhering to thesurface of the workpiece such as a substrate. Furthermore, theelectrolytic processing of a substrate can be effected even by solelyusing pure water or ultrapure water. This obviates the possibility thatimpurities such as an electrolyte will adhere to or remain on thesurface of the substrate, can simplify a cleaning process after theremoval processing, and can remarkably reduce a load upon waste liquiddisposal.

FIG. 31 is a vertical sectional view schematically showing anelectrolytic processing apparatus 534 according to a seventh embodimentof the present invention, and FIG. 32 is a plan view of the electrolyticprocessing apparatus 534 of FIG. 31. As shown in FIG. 31, theelectrolytic processing apparatus 534 includes a pivot arm 540 that canpivot horizontally and move vertically, a substrate holder 542,supported at the free end of the pivot arm 540, for attracting andholding the substrate W with its front surface facing downward(face-down), a disk-shaped electrode section 544 positioned beneath thesubstrate holder 542, and a power source 546 connected to the electrodesection 544. A film-like ion exchanger 547 is mounted on the uppersurface of the electrode section 544.

The pivot arm 540, which pivots horizontally by the actuation of a motor548 for pivoting, is connected to the upper end of a pivot shaft 550.The pivot shaft 550, which moves up and down integrated with the pivotarm 540 via a ball screw 552 by the actuation of a motor 554 forvertical movement, is engaged with the ball screw 552 that extendsvertically.

The substrate holder 542 is connected to a rotating motor 556 as a firstdrive element that is allowed to move the substrate W held by asubstrate holder 542 and the electrode section 544 relatively to eachother. The substrate holder 542 is rotated by the actuation of the motor556. The pivot arm 540 can swing horizontally and move vertically, asdescribed above, the substrate holder 542 can pivot horizontally andmove vertically integrated with the pivot arm 540. The electrode section544 is directly connected to a hollow motor 560 as a second driveelement that is allowed to move the substrate W and the electrodesection 544 relatively to each other. The electrode section 544 isrotated by the actuation of the hollow motor 560.

A pure water nozzle 562 as a pure water supply section is disposed abovethe electrode section 544 and extends in the radial direction of theelectrode section 544. The pure water nozzle 562 has a plurality ofsupply ports for supplying pure water or ultrapure water to the uppersurface of the electrode section 544. Pure water herein refers to awater having an electric conductivity of not more than 10 μS/cm, andultrapure water refers to a water having an electric conductivity of notmore than 0.1 μS/cm. The use of pure water or ultrapure water containingno electrolyte upon electrolytic processing can prevent impurities suchas an electrolyte from adhering to and remaining on the surface of thesubstrate W. Further, copper ions or the like dissolved duringelectrolytic processing are immediately caught by the ion exchanger 547through the ion-exchange reaction. This can prevent the dissolved copperions or the like from re-precipitating on the other portions of thesubstrate W, or from being oxidized to become fine particles whichcontaminate the surface of the substrate W.

Instead of pure water or ultrapure water, as described above, a liquidhaving an electric conductivity of not more than 500 μS/cm or anyelectrolytic solution, for example, an electrolytic solution obtained byadding an electrolyte to pure water or ultrapure water may be used.

FIG. 33 is a plan view showing the electrode section 544, and FIG. 34 isan enlarged view of a portion of the electrode section 544 of FIG. 33.As shown in FIGS. 33 and 34, the electrode section 544 includes adisk-shaped feeding electrode 570 and a large number of processingelectrodes 572 disposed in almost the whole surface of the feedingelectrode 570. Each processing electrode 572 is separated from thefeeding electrode 570 by an insulator 574. The upper surfaces of thefeeding electrode 570 and the processing electrodes 572 are coveredintegrally with the above-described ion exchanger 547. The processingelectrodes 572 are of the same shape, and are disposed in almost theentire surface of the feeding electrode 570 such that when the substrateW and the electrode section 544 are moved relatively, the presencefrequencies of processing electrodes 570 at every points in theto-be-processed surface of the substrate W become substantially equal.

According to this embodiment, the feeding electrode 570 is connected viaa slip ring 564 (see FIG. 31) to the anode of the power source 546, andthe processing electrodes 572 are connected via the slip ring 564 to thecathode of the power source 546. In processing of copper, for example,electrolytic processing action occurs on the cathode side. Accordingly,the electrode connected to the cathode becomes a processing electrodeand the electrode connected to the anode becomes a feeding electrode.

According to the electrolytic processing apparatus 534 of thisembodiment, a substrate W, having a copper film 6 (see FIG. 1B) as aconductive film (to-be-processed portion) formed in the surface, isplaced on a pusher 566 (see FIG. 32) of the electrolytic processingapparatus 534.

The substrate W on the pusher 566 is attracted and held by the substrateholder 542, and the arm 540 is moved to move the substrate holder 542holding the substrate W to a processing position right above theelectrode section 544. Next, the vertical movement motor 554 is drivento lower the substrate holder 542 so as to bring the substrate W, heldby the substrate holder 542, close to or into contact with the surfaceof the ion exchanger 547 of the electrode section 544. Thereafter, thehollow motor 560 is driven to rotate the electrode section 544 and therotating motor 556 is driven to rotate the substrate holder 542 and thesubstrate W, thereby allowing the substrate W and the electrode section544 to make a relative movement (eccentric rotational movement). Whileallowing the substrate W and the electrode section 544 to make therelative movement, pure water or ultrapure water is supplied from thesupply ports of the pure water nozzle 562 to between the substrate W andthe electrode section 544, and a given voltage is applied from the powersource 546 to between the processing electrodes 572 and the feedingelectrode 570, thereby carrying out electrolytic processing of theconductive film (copper film 6) in the surface of the substrate W at theprocessing electrodes (cathode) 572 through the action of the hydrogenions and hydroxide ions generated with the aid of the ion exchanger 547.

When a large number of electrodes are provided as in the case of thisembodiment, even with the use of the same shape of electrodes, there maybe a slight difference in contact area or in height between therespective electrodes. Further, the thickness of an ion exchangermounted on the electrodes may be slightly different and fixing of theion exchanger may be uneven between the respective electrodes.Accordingly, the processing amount per unit time will practically differbetween the respective electrodes. According to this embodiment, whenthe electrode section 544 and the substrate W are allowed to make arelative movement during electrolytic processing, a plurality ofprocessing electrodes 572, which are uneven in the processing rate perunit time, can pass every point in the to-be-processed surface of thesubstrate W. The processing electrodes 572 and the workpiece W areallowed to make a relative movement so that the largest possible numberof processing electrodes 572, which are uneven in the processing amountper unit time, can pass every point in the to-be-processed surface ofthe substrate W. Accordingly, even when the processing rate variesbetween the respective processing electrodes 572, the variation ofprocessing rate can be equated, enabling equalization of the processingrate on a nm/min order over the entire surface of the substrate W.

It is desired that the processing electrodes 572, having equal height,be embedded in the feeding electrode 570 such that their surfaces (uppersurfaces) are flush with the surface of the feeding electrode 570. Thisensures an even distance between the surface of each electrode and aworkpiece, preventing different distances between electrodes and aworkpiece causing a variation of the resistances therebetween, leadingto a variation of electric currents.

It is possible to group some of the processing electrodes 572, andcontrol voltage or electric current for each group independently.

It is to be noted here that when a liquid like ultrapure water whichitself has a large resistivity is used, the electric resistance can belowered by bringing the ion exchanger 547 into contact with thesubstrate W, whereby the requisite voltage can also be lowered and hencethe power consumption can be reduced. The “contact” does not imply“press” for giving a physical energy (stress) to a workpiece as in CMP.Accordingly, the electrolytic processing apparatus 534 of thisembodiment employs the vertical-movement motor 554 for bringing thesubstrate W into contact with or close to the electrode section 544, anddoes not have such a press mechanism as usually employed in a CMPapparatus that presses a substrate against a polishing member. Thisholds also for the below-described embodiments. In this regard,according to a CMP apparatus, a substrate is pressed against a polishingsurface generally at a pressure of about 20-50 kPa, whereas in theelectrolytic processing apparatus 534 of this embodiment, the substrateW may be contacted with the ion exchanger 547 at a pressure of less than20 kPa. Even at a pressure less than 10 kPa, a sufficient removalprocessing effect can be achieved.

Though in this embodiment the electrode section 544 and the substrate Ware both rotated such that they make an eccentric rotational movement,any relative movement may be employed insofar as to it allows aplurality of processing electrodes to pass every point in theto-be-processed surface of a workpiece. Such a relative movement mayinclude a rotational movement, a reciprocating movement, an eccentricrotational movement, a scroll movement, and any combination of thesemovements.

Further, in the preceding embodiment, the processing electrodes and thefeeding electrode may be replaced with each other. FIGS. 35 and 36 showan electrode section according to an eighth embodiment of the presentinvention, in which the processing electrodes and the feeding electrodeof the electrode section of the seventh embodiment are replaced witheach other. As shown in FIGS. 35 and 36, an electrode section 544 a ofthis embodiment includes a disk-shaped processing electrode 546 a and alarge number of feeding electrodes 548 a disposed in almost the wholesurface of the processing electrode 546 a. Each feeding electrode 548 ais separated from the processing electrode 546 a by an insulator 550 a.The upper surfaces of the processing electrode 546 a and the feedingelectrodes 548 a are covered integrally with the above-described ionexchanger 547 (see FIG. 31). The feeding electrodes 548 a are of thesame shape, and are disposed in almost the entire surface of theprocessing electrode 546 a such that when the substrate W and theelectrode section 544 a are moved relatively, the presence frequenciesof feeding electrodes 548 a at every points in the to-be-processedsurface of the substrate W become substantially equal.

This embodiment employs the single processing electrode 546 a. Even withthe single processing electrode, however, the processing amount per unittime may vary at some points. According to this embodiment, when theelectrode section 544 a and the substrate W are allowed to make arelative movement during electrolytic processing, a plurality of pointsin the processing electrode 546 a, which are uneven in the processingrate per unit time, can pass every point in the to-be-processed surfaceof the substrate W. The electrode section 544 a and the substrate W areallowed to make a relative movement so that the largest possible numberof points in the processing electrode 546 a which are uneven in theprocessing amount per unit time, can pass every point in theto-be-processed surface of the substrate W. Accordingly, even when theprocessing rate varies in the processing electrode 546 a, the variationof processing rate can be equated, enabling equalization of theprocessing rate on a nm/min order over the entire surface of thesubstrate W.

As with the preceding embodiment, it is desired that the feedingelectrodes 548 a, having equal height, be embedded in the processingelectrode 546 a such that their surfaces (upper surfaces) are flush withthe surface of the processing electrode 546 a. Further, it is possibleto group some of the feeding electrodes 548 a, and control voltage orelectric current for each group independently.

FIG. 37 is a plan view showing an electrode section 544 b of anelectrolytic processing apparatus according to a ninth embodiment of thepresent invention, and FIG. 38 is an enlarged view of a portion of theelectrode section 544 b of FIG. 37. As shown in FIGS. 37 and 38, theelectrode section 544 b includes a disk-shaped electrode plate 546 bformed of an insulating material, such as a resin, and a large number ofelectrodes 548 b, having the same shape, disposed in almost the wholesurface of the electrode plate 546 b. Each electrode 548 b, with itsperiphery covered with an insulator 550 b, is embedded in the electrodeplate 546 b. The upper surfaces of the electrodes 548 b are coveredintegrally with the above-described ion exchanger 547 (see FIG. 31).

Of the electrodes 548 b which are disposed in lines in a lattice formaccording to this embodiment, electrodes 548 c positioned in every otherlongitudinal line are connected via the slip ring 564 (see FIG. 31) tothe anode of the power source 546, and electrodes 548 d positioned inthe other lines are connected via the slip ring 564 to the cathode ofthe power source 546. The electrodes 548 c connected to the anode of thepower source 546 serve as feeding electrodes, and the electrodes 548 dconnected to the cathode of the power source 546 serve as processingelectrodes. The feeding electrodes 548 c and the processing electrodes548 are thus disposed in almost the entire surface of the electrodesection 544 b such that when the electrode section 544 b and a substrateW are moved relatively, the presence frequencies of feeding electrodes548 c and processing electrodes 548 d at every points in theto-be-processed surface of the substrate W become substantial equal. Asdescribed hereinabove, depending upon the material to be processed, theelectrodes connected to the cathode of the power source may serve asfeeding electrodes, and the electrodes connected to anode may serve asprocessing electrodes.

As with the preceding embodiments, in light of the overall flatness ofthe electrode section, it is desired that the electrodes 548 b, havingequal height, be embedded in the electrode plate 546 b such that theirsurfaces (upper surfaces) are flush with the surface of the electrodeplate 546 b. Depending upon the processibility of the electrode section544 b, however, the electrodes 548 b may protrude of the order ofseveral μm from the electrode plate 546 b. Further, it is possible togroup some of the feeding electrodes 548 c and the processing electrodes548 d, and control voltage or electric current for each groupindependently.

According to this embodiment, the number of the feeding electrodes 548 cis made substantially the same as the number of the processingelectrodes 548 d. Depending upon the processing conditions, however, therespective numbers of the feeding electrodes 548 c and of the processingelectrodes 548 d may arbitrarily be changed. For example, the number ofprocessing electrodes may be increased in order to increase theprocessing rate. Further according to this embodiment, the entiresurface of the electrode plate 546 b is covered with the ion exchangerso that electrolytic processing can be carried out with the use ofultrapure water. When using an electrolytic solution, however, it ispossible to cover the entire surface of the electrode plate with a scrubmember (liquid-permeable one such as a porous material).

As described hereinabove, the electrolytic processing apparatus 534according to this embodiment, a workpiece, such as a substrate, can beeffected through electrochemical action, in the place of CMP treatment,for example, without causing any physical defects in the workpiece thatwould impair the properties of the workpiece. Accordingly, the presentinvention can omit a CMP treatment entirely or at least reduce a loadupon CMP, and can effectively remove (clean) matter adhering to thesurface of the workpiece such as a substrate. Furthermore, theelectrolytic processing of a substrate can be effected even by solelyusing pure water or ultrapure water. This obviates the possibility thatimpurities such as an electrolyte will adhere to or remain on thesurface of the substrate, can simplify a cleaning process after theremoval processing, and can remarkably reduce a load upon waste liquiddisposal.

FIGS. 39 and 40 show a electrolytic processing apparatus 636 aprovidedwith a fixing structure for fixing an ion exchanger according toa tenth embodiment of the present invention. As shown in FIGS. 39 and40, the electrolytic processing apparatus 636 a includes a substrateholder 646, supported at the free end of a pivot arm 644 that can pivothorizontally, for attracting and holding the substrate W with its frontsurface facing downward (face down), and, positioned beneath thesubstrate holder 646, a disk-shaped electrode section 648 made of aninsulating material. The electrode section 648 has, embedded therein,fan-shaped processing electrodes 650 and feeding electrodes 652 that aredisposed alternately with their surfaces (upper faces) exposed. Afilm-like ion exchanger 656 is mounted on the upper surface of theelectrode section 648 so as to cover the surfaces of the processingelectrodes 650 and the feeding electrodes 652.

In this embodiment, as an example of the electrode section 648 havingthe processing electrodes 650 and the feeding electrodes 652, such onethat has a slight larger diameter than that of the substrate W isemployed so that the entire surface of the substrate W may undergoelectrolytic processing at the same time by the relative movement(scroll movement) of the electrode section 648.

The pivot arm 644, which moves up and down via a ball screw 662 by theactuation of a motor 660 for vertical movement, is connected to theupper end of a shaft 666 that rotates by the actuation of a motor 664for swinging. The substrate holder 646 is connected to a motor 668 forrotation that is mounted on the free end of the pivot arm 644, and isallowed to rotate by the actuation of the motor 668 for rotation.

The electrode section 648 is connected directly to a hollow motor 670,and is allowed to make the scroll movement (translational rotationmovement) by the actuation of the hollow motor 670. A through-hole 648 aas a pure water supply section for supplying pure water, preferablyultrapure water, is formed in the central portion of the electrodesection 648. The through-hole 648 a is connected to a pure water supplypipe 672 that vertically extends inside the hollow motor 670 via athrough-hole 673 a formed inside the crank shaft 673 connected directlyto the drive shaft of the hollow motor 670 for scroll movement. Purewater or ultrapure water is supplied through the through-hole 648 a, andvia the ion exchanger 656, is supplied to the entire processing surfaceof the substrate W.

According to this embodiment, a plurality of fan-shaped electrode plates676 are disposed in the upper surface of the electrode section 648 inthe circumferential direction of the electrode section 648 so that thesurfaces of the electrode plates 676 lie substantially on the sameplane, and cathode and anode of a power source 680 are alternatelyconnected to the electrode plates 676. The electrode plates 676connected to the cathode of the power source 680 become the processingelectrodes 650 and the electrode plates 676 connected to the anodebecome the feeding electrodes 652.

By thus disposing the processing electrodes 650 and the feedingelectrodes 652 separately and alternately in the circumferentialdirection of the electrode section 648, fixed feeding portions to supplyelectricity to a conductive film (portion to be processed) of thesubstrate is not needed, and processing can be effected to the entiresurface of the substrate. Further, be changing the positive and negativein a pulse manner or alternately, an electrolysis product can bedissolved and the flatness of the processed surface can be enhanced bythe multiplex repetition of processing.

The ion exchanger 656 is fixed in the electrode section 648 tightly onthe upper surfaces of the processing electrodes 650 and the feedingelectrodes 652 which are embedded in the electrode section 648 formed ofan insulating material. More specifically, the electrode section 648includes a large-diameter base 648 b and a small-diameter columnarelectrode support 648 c formed integrally to the upper portion of thebase 648 b. In fixing the ion exchanger 656, the ion exchanger 656 isallowed to cover the whole surface of the electrode support 648 c andthe electrode plates 676, while a peripheral portion of the ionexchanger 656 is positioned between the electrode support 648 c and afixing jig 690 which is engageable with the electrode support 648 c andformed of an insulating material. The fixing jig 690 is pressed intoengagement with the electrode support 648 c to fix the fixing jig 690 tothe electrode support 648 c, thereby sandwiching the peripheral portionof the ion exchanger 656 between the inner circumferential surface ofthe fixing jig 690 and the outer circumferential surface of theelectrode support 648 c and thus fixing the ion exchanger 656 to theelectrode support 648 c, whereby the ion exchanger 656 is fixed tightlyon the exposed surfaces of the processing electrodes 650 and the feedingelectrodes 652 in an evenly stretched (tense) state.

Thus, as shown in FIG. 40, the ion exchanger 656 is evenly stretchedoutwardly due to frictional force between the fixing jig 690, the ionexchanger 656 and the electrode support 648 c produced when pressing thefixing jig 690 into engagement with the columnar electrode support 648c, and the ion exchanger 656 is thus evenly stretched into a tensestate, whereby the ion exchanger is automatically fixed tightly on thesurface of the electrode support 648 c.

The fixing jig 690 is pressed into contact with the base 648 b. Further,the peripheral portion of the fixing jig 690 is pressed against the base648 b by a holding jig 692 having a hook shape in cross-section, and theskirt portion 692 a of the holding jig 692 is fixed to the electrodesection 648 by bolts 694, thereby preventing disengagement of theholding jig 690. The holding jig 692 may be fixed to the electrodesection 648 by other fixing means, such as a pin or a crank.

The tension applied to the ion exchanger 656 can be adjusted by changingthe height of protrusion of the electrode support 648 c. Alternatively,as shown in FIG. 41, a ring-shaped spacer 696 may be interposed betweenthe base 648 b of the electrode section 648 and the fixing jig 690. Thetension applied to the ion exchanger 656 may be adjusted by adjustingthe thickness “a” of the spacer 696.

As shown in FIG. 42A, the fixing jig 690 may be composed of a pair ofdivided jigs 690 a, 690 b, and the pair of divided jigs 690 a, 690 b,with the ion exchanger 656 at its peripheral portion sandwiched intherebetween and provisionally fixed by means of a bolt, etc., may bepressed into engagement with the electrode support 648 c of theelectrode section 648, as shown in FIG. 42B. This can prevent slippingbetween the ion exchanger 656 and the fixing jig 690 upon the press-inof the fixing jig 690, enabling the ion exchanger 656 to be fixed alwaysin a tense state. Further, the tension applied to the ion exchanger 656can be adjusted by adjusting the thickness “b” of the upper divided jig690 a.

The operation of the electrolytic processing apparatus 636 a inelectrolytic processing (electrolytic polishing) is substantially thesame as that of the above-described electrolytic processing apparatus334 shown in FIG. 17, hence a description thereof is omitted.

FIGS. 43 and 44 show an electrolytic processing apparatus 636 baccording to an eleventh embodiment of the present invention. Accordingto the electrolytic processing apparatus 636 b, a long ion exchanger 656a is stretched between a supply shaft 702 and a take-up shaft 704,provided at the both ends of a support 700, and the take-up shaft 704 isrotated by means of a take-up motor to take up the ion exchanger 656 asequentially. Further, electrolytic processing apparatus 636 b isprovided with an ion exchanger-fixing device 706 for fixing the ionexchanger 656 a. The other construction is the same as the apparatusshown in FIGS. 39 and 40.

The ion exchanger-fixing device 706 includes an electrodesection-elevating mechanism 708 for vertically moving the electrodesection 648, and a fixing jig-elevating mechanism 710 for verticallymoving the fixing jig 690 disposed above the electrode section 648. Theion exchanger 656 a is allowed to travel between the electrode section648 and the fixing jig 690. While the ion exchanger 656 a is stopped,the electrode section 648 is raised and the fixing jig 690 is lowered soas to sandwich the ion exchanger 656 a therebetween. The fixing jig 690is then pressed into engagement with the electrode support 648 c of theelectrode section 648 to thereby fix the fixing jig 690, whereby the ionexchanger 656 a is fixed to the electrode support 648 c in an evenlystretched state.

According to this embodiment, the electrode section 648 is provided onthe support 700 that is allowed to rotate by the actuation of the hollowmotor 670. The electrode section 648 is thus allowed to make arotational movement, not a scroll movement. Accordingly, the electrodeplates 676 are connected alternately to the cathode and to the anode ofthe power source 680 via the slip ring 678.

According to this embodiment, when part of the ion exchanger 656 a,which has been fixed by the ion exchanger-fixing device 706 and is inuse for processing, is stained for example, the electrode section 648 islowered while the fixing jig 690 is raised to release the fixing of theion exchanger 656 a and, after allowing the ion exchanger 656 a totravel a necessary distance, the electrode section 648 is raised whilethe fixing jig 690 is lowered to fix the ion exchanger 656 a. In such amanner, exchanges of the ion exchanger 656 a can be carried out in asuccessive manner. Further, the ion exchanger 656 a can be used inelectrolytic processing while it is kept fixed tightly on the surface ofthe processing electrodes 650 and the feeding electrodes 652.

FIG. 45 shows an electrolytic processing apparatus according to atwelfth embodiment of the present invention. According to thisembodiment, one drive shaft 720 and three driven shafts 722 are disposedin a trapezoidal arrangement, and an endless form of ion exchanger 656 bis stretched on the shafts 720, 722, so that it can travel in onedirection and circulate. Part of the ion exchanger 656 b traveling onthe upper side is to be fixed by the ion exchanger-fixing device 706 andused in processing, and part of the ion exchanger 656 b traveling on thelower side is to be regenerated in a regeneration section 724 providedin the traveling route.

This embodiment makes it possible to fix part of the endless ionexchanger 656 b and use that part for processing while regeneratingother part of the ion exchanger 656 b, not in use for processing, in theregeneration section 724, and after allowing the ion exchanger 656 b totravel in one direction, fix the regenerated part of ion exchanger 656 bfor use in processing. A repetition of this operation enablescirculation and repeated uses of the endless ion exchanger 656 b.

Regeneration of an ion exchanger is effected by exchange of an ioncaptured by the ion exchanger for hydrogen ion in the case of a cationexchanger, and for hydroxide ion in the case of an anion exchanger. Whencarrying out electrolytic processing of e.g. copper by using as an ionexchanger a cation exchanger having the cation-exchanger group, copperis captured by the cation-exchange group. Progress of the consumption ofthe cation-exchange group by copper makes it impossible to continue theelectrolytic processing. When electrolytic processing of copper iscarried out by using as an ion exchanger an anion exchanger having theanion-exchange group, on the other hand, fine particles of a copperoxide are produced and the particles adhere to the surface of the ionexchanger (anion exchanger). Such particles on the ion exchanger cancontaminate the surface of a next substrate to be processed.Regeneration of such a consumed or stained ion exchanger can prevent theproblems.

FIG. 47 shows an example of the regeneration section 724. Theregeneration section 724 comprises a fixed regeneration electrodeportion 732 in which one electrode 730 for regeneration, of a pair, isembedded with its surface exposed, a movable regeneration electrodeportion 738 which is vertically movable and holds the other electrode734 for regeneration, of a pair, whose surface is covered with an ionexchanger 736 for regeneration, a liquid supply nozzle 740 for supplyinga liquid for regeneration between the electrode portions 732, 738, and aregeneration power source 742 for applying a regeneration voltagebetween the pair of electrodes 730, 734 for regeneration.

The ion exchanger 736 for regeneration has the same type of theion-exchange group as the ion exchanger 656 b to be regenerated. Thatis, when a cation exchanger having a cation-exchange group is used asthe ion exchanger 656 b, a cation exchanger is used also as the ionexchanger 736 for regeneration. When an anion exchanger having ananion-exchange group is used as the ion exchanger 656 b to beregenerated, an anion exchanger is used also as the ion exchanger 736for regeneration.

In operation, the surface of the electrode 730 of the fixed regenerationelectrode portion 732 is covered with the ion exchanger 656 b to beregenerated. The movable regeneration electrode portion 738 is loweredso that the ion exchanger 736 for regeneration is brought close to orinto contact with the surface (upper surface) of the ion exchanger 656 bto be regenerated. Thereafter, a regeneration voltage is applied betweenthe electrodes 730, 734 such that the electrode on the side of the ionexchanger 736 for regeneration, i.e. the electrode 734, has the oppositepolarity to the polarity of the ion exchanger 656 b to be regenerated.Thus, when a cation exchanger having a cation-exchange group is used asthe ion exchanger 656 b, the electrode 734 is made a cathode and theelectrode 730 is made an anode. Conversely, when an anion exchanger isused as the ion exchanger 656 b, the electrode 734 is made an anode andthe electrode 730 is made a cathode. At the same time, pure water orultrapure water is supplied from the liquid supply nozzle 740 to thespace between the electrode portions 732, 738 so as to fill the spacewith pure water or ultrapure water, thereby immersing the ion exchanger656 b to be regenerated and the ion exchanger 736 for regeneration inpure water or ultrapure water.

By the above operation, through an ion-exchange reaction utilizing theion exchanger 656 b as a solid electrolyte, ions in the ion exchanger656 b to be regenerated are moved into the ion exchanger 736 forregeneration. Regeneration of the ion exchanger 656 b is thus effected.When a cation exchanger is used as the ion exchanger 656 b, cationstaken in the ion exchanger 656 b move into the ion exchanger 736 forregeneration; and when an anion exchanger is used as the ion exchanger656 b, anions taken in the ion exchanger 656 b move into the ionexchanger 736 for regeneration, whereby the ion exchanger 656 b isregenerated.

As described above, instead of pure water or ultrapure water, it is alsopossible to use a liquid having an electric conductivity of not morethan 500 μS/cm or an electrolytic solution.

FIG. 48 shows another example of the regeneration section 724. Themovable regeneration electrode portion 738 of this example has adownwardly-open circular depression 738 a. The lower opening of thedepression 738 a is closed with the ion exchanger 736 for regeneration,whereby a discharge portion 750, defined by the depression 738 a and theion exchanger 736 for regeneration, is formed. A disk-shaped electrode734 is mounted in the bottom of the depression 738 a. Further, a liquidinlet 752 and a liquid outlet 754, communicating with peripheralportions of the discharge portion 750, are provided at the both ends inthe diametrical direction of the movable regeneration electrode portion738. The liquid inlet 752 and the liquid outlet 754 are respectivelyconnected to a liquid inlet pipe 756 and to a liquid outlet pipe 758.The other construction is substantially the same as the precedingexample shown in FIG. 47.

According to this example, in regenerating the ion exchanger 656 b, aliquid is supplied from the liquid inlet pipe 756 into the dischargeportion 750 so as to create a flow of the liquid that flows in onedirection in the discharge portion 750 and is discharged from the liquidoutlet 758, and immerse the electrode 734 in the liquid. Ions in the ionexchanger 656 b are moved toward the electrode 734, passed through theion exchanger 736 for regeneration and introduced into the dischargeportion 750. The ions, which have moved into the discharge portion 750,are discharged out of the system by the flow of the liquid supplied intothe discharge portion 750. The ion exchanger 656 b can thus beregenerated more efficiently.

It is desirable that the liquid to be supplied into the dischargeportion 750 be a liquid that has a high electric conductivity and doesnot form a hardly soluble or insoluble compound by a reaction with ionsremoved from the ion exchanger. Examples of such a liquid may include anelectrolytic solution, in particular, sulfuric acid with a concentrationof 1 wt % or more, which may be employed in generating an ion exchangerthat has been used in electrolytic processing of copper.

FIG. 46 shows the main portion of an electrolytic processing apparatusaccording to a thirteenth embodiment of the present invention. Accordingto this embodiment, a pair of supply/take-up shafts 760 and a pair ofintermediate shafts 762 are disposed in a gate-like arrangement on bothsides of the ion exchanger-fixing device 706. An ion exchanger 656 c cantravel in two directions (opposite directions). Further, tworegeneration sections 724 are disposed respectively between onesupply/take-up shaft 760 and one intermediate shaft 762, and between theother supply/take-up shaft 760 and the other intermediate shaft 762. Theother construction is the same as the embodiment shown in FIG. 45.

This embodiment makes it possible to fix part of the ion exchanger 656 cby the ion exchanger-fixing device 706 and use that part for processingwhile regenerating other part of the ion exchanger 656 c, not in use forprocessing, in one of the regeneration section 724, and exchange thepart of ion exchanger 656 c, which has been used in processing, for theregenerated part of ion exchanger 656 c. Thus, referring to FIG. 46,when the ion exchanger 656 c travels leftward, the portion of ionexchanger 656 c regenerated in the right regeneration section 724,positioned downstream in the traveling direction, is used forprocessing; when the ion exchanger 656 c travels rightward, the portionof ion exchanger 656 c regenerated in the left regeneration section 724,positioned downstream in the traveling direction, is used forprocessing. A repetition of the above operation enables repeated uses ofthe ion exchanger 656 c e.g. until its mechanical deterioration.

In the above-described embodiments, a ring-shaped fixing jig 690, whichcovers the whole circumferential surface of the electrode support 648 c,is used so that a tension may be applied evenly over the entire surfaceof the ion exchanger (656 a through 656 c). However, it is also possibleto dispose a pair of rod-like fixing jigs 690 a back and forth of theion exchanger (656 a through 656 c) in the traveling direction, andlower the fixing jigs 690 a to fix the ion exchanger (656 a through 656c). The point of the fixing jig is to be positioned outside of suchregion of the ion exchanger (656 a through 656 c) that is used forprocessing and it can hold the ion exchanger under tension. The shape offixing jig also is not limited to a ring shape, and a variety of shapesmay be used mainly depending upon and in conformity with the shape ofthe electrode.

As described hereinabove, according to the electrolytic processingapparatuses 636 a, 636 b of the above-described embodiments, by simplypressing the fixing jig into engagement with the electrode support ofthe electrode section, the ion exchanger can be evenly stretchedoutwardly into a tense state, and the ion exchanger can be automaticallyfixed tightly on the surface of the electrode. The present inventionthus makes it possible to easily and quickly fix an ion exchangertightly on the surface of an electrode.

Although certain preferred embodiments of the present invention havebeen shown and described in detail, it should be understood that variouschanges and modifications may be made therein without departing from thescope of the appended claims.

The present application is based on the U.S. Patent application filed onJan. 7, 2003, which is a continuation-in-part of U.S. application Ser.No. 10/296,333 which was filed Nov. 22, 2002, the entire disclosure ofwhich is hereby incorporated by reference.

Industrial Applicability

This invention relates to an electrolytic processing apparatus andmethod useful for processing a conductive material formed in the surfaceof a substrate, especially a semiconductor wafer, or for removingimpurities adhering to the surface of a substrate.

1. An electrolytic processing apparatus, comprising: a processingelectrode that can come close to or into contact with a workpiece; afeeding electrode for feeding electricity to the workpiece; an ionexchanger disposed in at least either between the workpiece and theprocessing electrode, or between the workpiece and the feedingelectrode; a fluid supply section for supplying a fluid between theworkpiece and the ion exchanger; and a plurality of power sources, eachfor applying a voltage between the processing electrode and the feedingelectrode; wherein at least one of the processing electrode and thefeeding electrode is electrically divided into a plurality of parts, andthe power sources apply each voltage to each of the divided electrodeparts and can control at least one of voltage and electric currentindependently for each of the divided electrode parts.
 2. Theelectrolytic processing apparatus according to claim 1, wherein thefluid is ultrapure water, pure water, a liquid having an electricconductivity of not more than 500 μS/cm.
 3. The electrolytic processingapparatus according to claim 1, wherein the power sources applyrespectively different constant voltages at least one time to each ofthe divided electrode parts.
 4. The electrolytic processing apparatusaccording to claim 1, wherein each of the power sources applies anelectric current or a voltage, which changes with time, to each of thedivided electrode parts.
 5. An electrolytic processing method,comprising: providing a processing electrode and a feeding electrode, atleast one of which is electrically divided into a plurality of parts;allowing a workpiece to be close to or in contact with the processingelectrode; feeding electricity from the feeding electrode to theworkpiece; disposing an ion exchanger between at least either betweenthe workpiece and the processing electrode, or between the workpiece andthe feeding electrode; supplying a fluid between the workpiece and theion exchanger; applying a voltage to each of the divided electrodeparts; and controlling at least one of voltage and electric currentindependently for each of the divided electrode parts.
 6. Theelectrolytic processing method according to claim 5, wherein the fluidis ultrapure water, pure water, a liquid having an electric conductivityof not more than 500 μS/cm.
 7. The electrolytic processing methodaccording to claim 5, wherein the control is effected such thatrespectively different constant voltages are applied at least one timeto each of the divided electrode portions.
 8. An electrolytic processingapparatus, comprising: a processing electrode; a feeding electrode forfeeding electricity to the workpiece; a holder for holding the workpiecethat can come close to or into contact with the processing electrode; anion exchanger disposed in at least either between the workpiece and theprocessing electrode, or between the workpiece and the feedingelectrode; a power source for applying a voltage between the processingelectrode and the feeding electrode; a fluid supply section forsupplying a fluid between the workpiece and at least one of theprocessing electrode and the feeding electrode, in which the ionexchanger is disposed; and a drive section for allowing the workpieceheld by the holder and the processing electrode to make a relativemovement; wherein a dummy member, at least the surface of which has anelectric conductivity, is disposed outside of the periphery of theworkpiece.
 9. The electrolytic processing apparatus according to claim8, wherein the dummy member makes the area of the portion of theworkpiece facing the processing electrode constant during the relativemovement of the workpiece and the processing electrode.
 10. Theelectrolytic processing apparatus according to claim 8, wherein theconductive portion of the dummy member is formed of an electrochemicallyinactive material.
 11. The electrolytic processing apparatus accordingto claim 8, wherein the conductive portion of the dummy member is formedof the same material as the workpiece.
 12. The electrolytic processingapparatus according to claim 8, wherein a buffering member is disposedbetween the workpiece and the dummy member.
 13. An electrolyticprocessing apparatus, comprising: a processing electrode having a largerdiameter than a workpiece; a feeding electrode for feeding electricityto the workpiece; a holder for holding the workpiece that can come closeto or into contact with the processing electrode; an ion exchangerdisposed in at least either between the workpiece and the processingelectrode, or between the workpiece and the feeding electrode; a powersource for applying a voltage between the processing electrode and thefeeding electrode; a fluid supply section for supplying a fluid to thespace between the workpiece and at least one of the processing electrodeand the feeding electrode, in which the ion exchanger is disposed; and adrive section for allowing the workpiece held by the holder and theprocessing electrode to make a relative movement in such a state thatthe center of movement of the processing electrode lies within the rangeof the workpiece.
 14. An electrolytic processing apparatus, comprising:a processing electrode having a larger diameter than a workpiece; afeeding electrode for feeding electricity to the workpiece; a holder forholding the workpiece that can come close to or into contact with theprocessing electrode and the feeding electrode; a power source forapplying a voltage between the processing electrode and the feedingelectrode; a fluid supply section for supplying a fluid between theworkpiece and the processing and feeding electrodes; and a drive sectionfor allowing the workpiece held by the holder and the processing andfeeding electrodes to make a relative movement in such a state that thecenter of movement of the processing electrode lies within the range ofthe workpiece.
 15. An electrolytic processing apparatus, comprising: aprocessing electrode having a larger diameter than a workpiece; aplurality of feeding electrodes disposed in a peripheral portion of theprocessing electrode; a holder for holding the workpiece that can comeclose to or into contact with the processing electrode; an ion exchangerdisposed in at least either between the workpiece and the processingelectrode or between the workpiece and the feeding electrodes; a powersource for applying a voltage between the processing electrode and thefeeding electrodes; a fluid supply section for supplying a fluid to thespace between the workpiece and at least one of the processing electrodeand the feeding electrodes, in which the ion exchanger is disposed; anda drive section for allowing the workpiece held by the holder and theprocessing electrode to make a relative movement in such a state that atleast one of the feeding electrodes always feeds electricity to theworkpiece.
 16. The electrolytic processing apparatus according to claim15, wherein the processing electrode comprises an outer processingelectrode defined by the peripheral portion in which the feedingelectrodes are disposed, and an inner processing electrode positioned onthe inner side of the outer processing electrode.
 17. The electrolyticprocessing apparatus according to claim 16, wherein the power sourcecontrols independently the respective voltages or electric currentsapplied to the outer processing electrode and to the inner processingelectrode.
 18. An electrolytic processing apparatus, comprising: aprocessing electrode having a larger diameter than a workpiece; aplurality of feeding electrodes disposed in a peripheral portion of theprocessing electrode; a holder for holding the workpiece that can comeclose to or into contact with the processing electrode and the feedingelectrodes; a power source for applying a voltage between the processingelectrode and the feeding electrodes; a fluid supply section forsupplying a fluid between the workpiece and the processing and feedingelectrodes; and a drive section for allowing the workpiece held by theholder and the processing and feeding electrodes to make a relativemovement in such a state that at least one of the feeding electrodesalways feeds electricity to the workpiece.
 19. The electrolyticprocessing apparatus according to claim 18, wherein the processingelectrode comprises an outer processing electrode defined by theperipheral portion in which the feeding electrodes are disposed, and aninner processing electrode positioned on the inner side of the outerprocessing electrode.
 20. The electrolytic processing apparatusaccording to claim 19, wherein the power source controls independentlythe respective voltages or electric currents applied to the outerprocessing electrode and to the inner processing electrode.
 21. Anelectrolytic processing method, comprising: providing a processingelectrode having a larger diameter than a workpiece and a feedingelectrode for feeding electricity to the workpiece; disposing an ionexchanger between the workpiece and at least one of the processingelectrode and the feeding electrode; applying a voltage between theprocessing electrode and the feeding electrode; allowing the workpieceto be close to or into contact with the processing electrode; supplyinga fluid between the workpiece and at least one of the processingelectrode and the feeding electrode, in which the ion exchanger isdisposed; and allowing the workpiece and the processing electrode tomake a relative movement in such a state that the center of movement ofthe processing electrode always lies within the range of the workpiece,thereby processing the surface of the workpiece.
 22. An electrolyticprocessing method, comprising: providing a processing electrode having alarger diameter than a workpiece and a feeding electrode for feedingelectricity to the workpiece; applying a voltage between the processingelectrode and the feeding electrode; allowing the workpiece to be closeto or into contact with the processing electrode and the feedingelectrode; supplying a fluid between the workpiece and the processingelectrode and feeding electrode; and allowing the workpiece and theprocessing and feeding electrodes to make a relative movement in such astate that the center of movement of the processing electrode alwayslies within the range of the workpiece, thereby processing the surfaceof the workpiece.
 23. An electrolytic processing method comprising:providing a processing electrode having a larger diameter than aworkpiece and a plurality of feeding electrodes disposed in a peripheralportion of the processing electrode; disposing an ion exchanger betweenthe workpiece and at least one of the processing electrode and thefeeding electrodes; applying a voltage between the processing electrodeand the feeding electrodes; allowing the workpiece to be close to orinto contact with the processing electrode; supplying a fluid betweenthe workpiece and at least one of the processing electrode and thefeeding electrodes, in which the ion exchanger is disposed; and allowingthe workpiece and the processing electrode to make a relative movementin such a state that at least one of the feeding electrodes always feedselectricity to the workpiece, thereby processing the surface of theworkpiece.
 24. An electrolytic processing method, comprising: providinga processing electrode having a larger diameter than a workpiece and aplurality of feeding electrodes disposed in a peripheral portion of theprocessing electrode; applying a voltage between the processingelectrode and the feeding electrodes; allowing the workpiece to be closeto or into contact with the processing electrode and the feedingelectrodes; supplying a fluid between the workpiece and the processingand feeding electrodes; and allowing the workpiece and the processingand feeding electrodes to make a relative movement in such a state thatat least one of the feeding electrodes always feeds electricity to theworkpiece, thereby processing the surface of the workpiece.
 25. Anelectrolytic processing method, comprising: allowing a workpiece to beclose to or into contact with a plurality of processing electrodes;applying a voltage between the processing electrodes and a feedingelectrode for feeding electricity to the workpiece; supplying a fluidbetween the workpiece and at least one of the processing electrodes andthe feeding electrode; and allowing the processing electrodes and theworkpiece to make a relative movement so that a plurality of processingelectrodes, which are uneven in the processing amount per unit time,pass every point in the to-be-processed surface of the workpiece,thereby processing the surface of the workpiece.
 26. The electrolyticprocessing method according to claim 25, wherein the feeding electrodecomprises a plurality of electrodes.
 27. The electrolytic processingmethod according to claim 25, wherein the plurality of processingelectrodes are disposed such that the presence frequencies of processingelectrodes at every points in the to-be-processed surface of theworkpiece become substantially equal during the relative movement. 28.The electrolytic processing method according to claim 26, wherein theplurality of feeding electrodes are disposed such that the presencefrequencies of feeding electrodes at every points in the to-be-processedsurface of the workpiece become substantially equal during the relativemovement.
 29. The electrolytic processing method according to claim 25,wherein the plurality of processing electrodes are of the same shape.30. The electrolytic processing method according to claim 25, whereinthe relative movement is one of a rotational movement, a reciprocatingmovement, an eccentric rotational movement and a scroll movement, or acombination thereof.
 31. The electrolytic processing method according toclaim 25, wherein an ion exchanger is disposed between the workpiece andat least one of the processing electrodes and the feeding electrode. 32.The electrolytic processing method according to claim 25, wherein thefluid is ultrapure water, pure water, a liquid having an electricconductivity of not more than 500 ìS/cm.
 33. An electrolytic processingmethod, comprising: allowing a workpiece to be close to or into contactwith a processing electrode; applying a voltage between the processingelectrode and a feeding electrode for feeding electricity to theworkpiece; supplying a fluid between the workpiece and at least one ofthe processing electrode and the feeding electrode; and allowing theprocessing electrode and the workpiece to make a relative movement sothat a plurality of points in the processing electrode, which are unevenin the processing amount per unit time, pass every point in theto-be-processed surface of the workpiece, thereby processing the surfaceof the workpiece.
 34. The electrolytic processing method according toclaim 33, wherein the feeding electrode is disposed such that thepresence frequencies thereof at every points in the to-be-processedsurface of the workpiece become substantially equal during the relativemovement.
 35. The electrolytic processing method according to claim 33,wherein the feeding electrode comprises a plurality of electrodes, andthe plurality of feeding electrodes are of the same shape.
 36. Theelectrolytic processing method according to claim 33, wherein therelative movement is one of a rotational movement, a reciprocatingmovement, an eccentric rotational movement and a scroll movement, or acombination thereof.
 37. The electrolytic processing method according toclaim 33, wherein an ion exchanger is disposed between the workpiece andat least one of the processing electrode and the feeding electrode. 38.The electrolytic processing method according to claim 33, wherein thefluid is ultrapure water, pure water, a liquid having an electricconductivity of not more than 500 μS/cm.
 39. An electrolytic processingapparatus, comprising: a plurality of processing electrodes; a feedingelectrode for feeding electricity to the workpiece; a holder for holdingthe workpiece that can come close to or into contact with the processingelectrodes; a power source for applying a voltage between the processingelectrodes and the feeding electrode; a fluid supply section forsupplying a fluid between the workpiece and one of the processingelectrodes and the feeding electrode; and a drive section for allowingthe processing electrodes and the workpiece to make a relative movementso that a plurality of processing electrodes, which are uneven in theprocessing amount per unit time, pass every point in the to-be-processedsurface of the workpiece held by the holder.
 40. The electrolyticprocessing apparatus according to claim 39, wherein the feedingelectrode comprises a plurality of electrodes.
 41. The electrolyticprocessing apparatus according to claim 39, wherein the plurality ofprocessing electrodes are disposed in the feeding electrode such thatthe presence frequencies of processing electrodes at every points in theto-be-processed surface of the workpiece become substantially equalduring the relative movement.
 42. The electrolytic processing apparatusaccording to claim 40, wherein the plurality of feeding electrodes aredisposed such that the presence frequencies of feeding electrodes atevery points in the to-be-processed surface of the workpiece becomesubstantially equal during the relative movement.
 43. The electrolyticprocessing apparatus according to claim 39, wherein the plurality ofprocessing electrodes are of the same shape.
 44. The electrolyticprocessing apparatus according to claim 42, wherein the relativemovement is one of a rotational movement, a reciprocating movement, aneccentric rotational movement and a scroll movement, or a combinationthereof.
 45. The electrolytic processing apparatus according to claim42, wherein an ion exchanger is disposed between the workpiece and atleast one of the processing electrodes and the feeding electrodes. 46.The electrolytic processing apparatus according to claim 42, wherein thefluid is ultrapure water, pure water, a liquid having an electricconductivity of not more than 500 μS/cm.
 47. An electrolytic processingapparatus comprising: a processing electrode; a feeding electrode forfeeding electricity to a workpiece; a holder for holding the workpiecethat can come close to or into contact with the processing electrodes; apower source for applying a voltage between the processing electrode andthe feeding electrode; a fluid supply section for supplying a fluidbetween the workpiece and at least one of the processing electrode andthe feeding electrode; and a drive section for allowing the processingelectrode and the workpiece to make a relative movement so that aplurality of points in the processing electrode, which are uneven in theprocessing amount per unit time, pass every point in the to-be-processedsurface of the workpiece held by the holder.
 48. The electrolyticprocessing apparatus according to claim 47, wherein the feedingelectrode is disposed such that the presence frequencies thereof atevery points in the to-be-processed surface of the workpiece becomesubstantial equal during the relative movement.
 49. The electrolyticprocessing apparatus according to claim 47, wherein the feedingelectrode comprises a plurality of electrodes, and the plurality offeeding electrodes are of the same shape.
 50. The electrolyticprocessing apparatus according to claim 47, wherein the relativemovement is one of a rotational movement, a reciprocating movement, aneccentric rotational movement and a scroll movement, or a combinationthereof.
 51. The electrolytic processing apparatus according to claim47, wherein an ion exchanger is disposed between the workpiece and atleast one of the processing electrode and the feeding electrode.
 52. Theelectrolytic processing apparatus according to claim 47, wherein thefluid is ultrapure water, pure water, a liquid having an electricconductivity of not more than 500 μS/cm, or an electrolytic solution.53. A fixing method for fixing an ion changer for use in electrolyticprocessing on an electrode, comprising: positioning an ion exchangerbetween an electrode support, which supports an electrode with itssurface exposed, and a fixing jig engageable with the periphery of theelectrode support; and engaging the fixing jig with the electrodesupport, thereby fixing the ion exchanger with its peripheral portionsandwiched in between the fixing jig and the electrode support.
 54. Thefixing method according to claim 53, wherein the fixing jig consists ofa pair of divided jigs, and the pair of divided jigs, with the ionexchanger at its peripheral portion sandwiched therebetween, is pressedinto engagement with the electrode support.
 55. A method for fixing anion exchanger for use in electrolytic processing on an electrode,comprising: disposing an ion exchanger-fixing jig outside of anelectrode; holding the ion exchanger by the ion exchanger-fixing jig;and attaching the ion exchanger-fixing jig to the electrode whileallowing the ion exchanger to be supported in a tense state on theelectrode.
 56. A fixing structure for fixing an ion exchanger for use inelectrolytic processing on an electrode, comprising: an electrodesupport that supports an electrode with its surface exposed; and afixing jig engageable with the periphery of the electrode support;wherein the electrode support and the fixing jig fix an ion exchanger bysandwiching therebetween a peripheral portion of the ion exchanger andstretching the ion exchanger over the surface of the electrode.
 57. Thefixing structure according to claim 56, wherein the fixing jig consistsof a pair of divided jigs, and an outer peripheral portion of the ionexchanger, outside of the portion covering the electrode support, issandwiched in between the fixing jigs.
 58. An electrolytic processingapparatus comprising an ion exchanger-fixing device, said ionexchanger-fixing device including; an electrode support that supports anelectrode with its surface exposed; and a fixing jig engageable with theperiphery of the electrode support; wherein the ion exchanger-fixingdevice fixes an ion exchanger by sandwiching a peripheral portion of theion exchanger in between the electrode support and the fixing jig. 59.The electrolytic processing apparatus according to claim 58, wherein theelectrode support and the fixing jig are allowed to move relatively tofix the ion exchanger by sandwiching the peripheral portion of the ionexchanger between the electrode support and the fixing jig.
 60. Theelectrolytic processing apparatus according to claim 58, wherein the ionexchanger, disposed between the electrode support and the fixing jig, iscapable of traveling.
 61. The electrolytic processing apparatusaccording to claim 60, wherein the ion exchanger has an endless form andis capable of traveling in one direction, and a regeneration section forregenerating the ion exchanger is provided in a traveling route of theion exchanger.
 62. The electrolytic processing apparatus according toclaim 60, wherein the ion exchanger is capable of traveling in twodirections, and two regeneration sections for regenerating the ionexchanger are provided on both sides of the electrode support in thetraveling direction of the ion exchanger.